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Reference  Htbrarp 


DC      FED  BY 


A  PRACTICAL  TREATISE 


Artificial  Crown-  and  Bridge- Work. 


GEORGE    EVANS. 


LECTURER   ON    CROWN-  AND   BRIDGE-WORK  IN"   THE  BALTIMORE  COLLEGE  OF  DENTAL  SURGERY: 
MEMBER   OF   THE   AMERICAN   DENTAL  ASSOCIATION',   AND  OF   THE   SOUTHERN 
DENTAL  ASSOCIATION;   HONORARY   MEMBER   OF  THE   MARY- 
LAND STATE   DENTAL   ASSOCIATION,   ETC, 


Third  Edition,  Revised  and  Enlarged. 


WITH     631     ILLUSTRATIONS. 


PHILADELPHIA: 

THE  S.  S.  "WHITE  DENTAL  MFG.  CO. 
1893. 


Copyright,  1888,  by  Gboege  Evans. 
Copyright,  1889,  by  George  Evans. 
Copyright,  1893,  by  George  Evans. 


To  the  Members 
of  the 

First  District  Dental  fiociety  of  the  jState  of  jYew   York, 
this  Book  is  respectfully  dedicated 

by 

THE  /HJTHOR, 


Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 
Columbia  University  Libraries 


http://www.archive.org/details/practicaltreatis1893evan 


PREFACE  TO  THE  THIRD  EDITION 


Crown-  and  bridge-work  has  now  received  professional  in- 
dorsement. A  recognized  and  honorable  position  in  dental 
prosthesis  has  been  accorded  to  it.  Its  teaching  has  been  added 
as  a  special  branch  to  the  curriculum  of  every  dental  college 
in  the  United  States  which  is  classed  among  those  imparting 
a  thoroughly  practical  and  advanced  education  to  its  students. 

As  the  methods  by  which  its  results  are  achieved  in  dental 
practice  become  better  understood,  its  great  advantages  are 
conceded. 

That  crown-  and  bridge-work  is  being  improved  in  methods 
of  practical  application,  and  that  the  sphere  of  its  usefulness  is 
widening,  is  evidenced  by  a  comparison  of  the  present  edition 
of  this  work  with  those  which  have  preceded  it. 

The  object  of  previous  editions  was,  as  stated  in  the  first 
edition,  to  assist  in  obtaining  a  proper  recognition  of  crown-  and 
bridge-work,  by  placing  before  the  dental  profession  a  practical 
treatise  on  the  subject  which  should  explain  in  a  liberal  and  im- 
partial manner  the  principles  involved,  and  as  well  outline  correct 
methods  of  practice.  In  preparing  the  present  revised  edition 
these  objects  have  been  kept  plainly  in  view,  and  the  author 
has  endeavored  also  to  better  meet  the  need  for  a  text-book  for 
college  and  post-graduate  study,  as  well  as  to  enhance  the  value 
of  the  volume  as  a  reference-book  for  the  practitioner. 

George  Evans. 

133  W.  34th  St.,  New  York, 
January,  1803. 


PREFACE  TO  THE  SECOND  EDITION. 


In  a  field  of  practice  so  new  as  that  of  which  this  volume 
treats  it  is  natural  that  changes  and  improvements  in  methods  and 
systems  should  be  evolved  with  unceasing  rapidity.  Although 
less  than  a  year  has  elapsed  since  the  publication  of  the  first 
edition,  the  revision  of  the  work  for  the  introduction  of  new 
matter  has  become  necessary  to  properly  fulfill  the  requirements 
of  a  practical  and  comprehensive  treatise. 

Professional  interest  in  the  subject  of  crown-  and  bridge-work 
continues  unabated.  Judging  from  the  space  its  discussion 
occupies  in  the  journals  and  the  proceedings  of  societies,  this 
branch  of  practice  is  gaining  in  favor.  Many  new  ideas  respect- 
ing it  have  reached  the  profession  through  each  of  the  channels 
named.  From  these  and  from  other  available  sources  careful 
selection  of  methods  and  appliances  possessing  merit  has  been 
made  which  by  incorporation  in  this  second  edition  should 
enhance  its  value  to  the  busy  practitioner. 

The  author  entertains  a  grateful  appreciation  of  the  compli- 
mentary acknowledgments  which  have  been  accorded  to  his 
efforts  and  intentions,  and  hopes  for  an  equally  favorable  estimate 
of  his  labors  in  connection  with  this  edition. 

George  Evans. 

New  York,  July,  1889. 


PREFACE  TO  THE  FIRST  EDITION. 


The  aim  of  the  author  in  preparing  this  treatise  is  to  supply 
an  admitted  want  in  dental  literature. 

Much  that  is  new  in  dentistry  and  much  more  that  is,  by 
many  practitioners  at  least,  only  imperfectly  understood,  is 
involved  in  crown-  and  bridge-work.  Properly  practiced  it 
approaches  a  fine  art;  but  misapprehension  of  the  principles 
underlying  it,  lack  of  judgment  in  their  application,  and  im- 
proper practice  have  conspired  to  prevent  its  general  acceptation 
by  the  profession,  and  it  has  in  consequence  been  only  partially 
indorsed  or  even  wholly  condemned  when  a  better  understanding 
would  have  insured  its  hearty  approval.  Still,  its  possibilities 
are  seen  to  be  so  great  that  at  present  no  other  branch  of 
dentistry  more  engages  the  attention  of  practitioners,  and  in  no 
other  is  a  livelier  interest  or  a  greater  desire  for  real  information 
manifested. 

The  subject  is  here  presented  almost  wholly  from  the  practical 
standpoint,  in  the  belief  that  the  utility  and  esthetic  advantages 
of  crown-  and  bridge-work  may  be  thus  more  readily  made 
apparent  to  the  practical  men  in  dentistry.  To  this  end  the 
various  methods  described  are  classified  in  systems,  and  their 
treatment  is  made  as  concise  as  their  importance  will  permit. 
Due  credit  is  given  where  the  methods  and  descriptions  of  others 
are  used. 

Acknowledgment  is  gratefully  rendered  to  Drs.  II.  A.  Parr, 
of  New  York  City,  E.  Parmly  Brown,  of  Flushing,  1ST.  Y.,  and 
M.  H.  Fletcher,  of  Cincinnati,  for  personal  assistance. 

George  Evans. 

New  York,  August,  1888. 


CONTENTS. 


PAGE 

Introduction 1 

Artificial  Crown-  and  Bridge-Work 5 

PART     I. 

PREPARATORY   TREATMENT   OF   TEETH   AND    ROOTS    FOR    CROWN-WORK. 

CHAPTER  I. 

The  Pulps  of  Teeth — Their  Preservation  or  Devitalization — Pulp- 
Capping 10 

CHAPTER  II. 

Devitalization  of  the  Pulp 16 

CHAPTER     III. 

Pulpless  Teeth — Preparation  of  Root-Canals — Their  Treatment, 
Disinfection,  and  Filling -1 

CHAPTER  IV. 

Chronic  Alveolar  Abscess 28 

CHAPTER  V. 
Shaping  Teeth  and  Roots  for  Crown-Work 33 

PART     II. 

ARTIFICIAL  CROWN- WORK. 

THE    PORCELAIN    SYSTEM. 

CHAPTER  I. 

Porcelain  Crowns 42 

The  Bonwill  Crown 43 

The  How  Crowns  and  Methods -19 

The  Gates  Crown. 56 

The  Foster  Crown 57 

The  Howland  Crown 57 

The  Logan,  Brown,  and  New  Richmond  Crowns 58 

Remarks  on  the  Use  of  Porcelain  Crowns 66 

xi 


xii  CONTEXTS. 

CHAPTER  II. 

PAGE 

Porcelain  Crown  with  Gold  Collar  Attachment 68 

CHAPTER  III. 
The  Weston  Crown 73 

CHAPTER  IV. 
Porcelain  Crowns  with  Rubber  or  Vulcanite  Attachment 76 

the  gold  system. 

CHAPTER  V. 

Porcelain  and  Gold  Crown  without  a  Collar 77 

With  a  Partial  Ferrule 78 

CHAPTER  VI. 

Gold  Collar  Crowns 79 

The  Construction  and  Adaptation  of  Collars 79 

CHAPTER  VII. 

Gold  Collar  Crowns  with  Porcelain  Fronts 85 

Incisors  and  Cuspids 85 

Bicuspids  and  Molars 88 

CHAPTER  VIII. 
All-Gold  Collar  Crowns  for  Bicuspids  and  Molars  constructed 

in  Sections 92 

Incisors  and  Cuspids 100 

CHAPTER  IX. 

The  Gold  Seamless  Cap  Crown 102 

Incisors,  Cuspids,  and  Bicuspids,  with  Porcelain  Fronts 102 

All-Gold  Seamless  Bicuspids  and  Molars 104 

CHAPTER  X. 

Gold  Seamless  Contour  Crowns 108 

Adjustment  of  Seamless  Contour  Crowns Ill 

CHAPTER  XI. 
Gold  Crowns  with  Porcelain  Fronts  for  Teeth  with  Living  Pulps  119 
Collar  Crowns  Hygienically  Considered 124 

CHAPTER  XII. 

Special  Forms  of  Gold  Crowns  with  Porcelain  Fronts 126 

The  Parr  Crown 126 

The  Leech  Crown 127 

The  Low  Crown 128 

The  Perry  Crown 130 


CONTENTS.  xiii 

CHAPTER   XIII. 

PAGE 

Crowning  Fractured  Teeth  and  Roots — Crowning  Molar  Roots 
decayed  apart  at  bifurcation — crowning  in  cases  of  irregu- 
LARITY      132 

Longitudinal  Fracture  of  the  Crown  and  Root 132 

Fracture  of  the  Crown  with  Slanting  Fracture  of  the  Root 133 

Perforation  of  a  Side  Wall  of  a  Root-canal  or  of  the  Dentine  at  the 

Bifurcation  of  the  Roots 134 

Crowning  Molar  Roots  decayed  apart  at  the  Bifurcation 135 

Dr.  Farrar's  Cantilever  Crown 135 

Methods  of  Crowning  in  Cases  of  Irregularity 136 

CHAPTER   XIV. 
Partial  Crowns 137 

CHAPTER   XV. 

Finishing  and  Polishing — Process  of  Cementation 145 

Finishing  and  Polishing  Crown-Work 145 

Insertion  and  Cementation 145 

Oxyphosphate  of  Zinc 145 

Gutta-Percha 148 

Amalgam 148 

PAET     III. 

BRIDGE-WORK. 

CHAPTER    I. 
Construction  of  Bridge-Work 158 

CHAPTER   II. 
Special  Processes  and  Appliances  in  Bridge-Work 171 

CHAPTER   III. 
Extension  Bridges 178 

CHAPTER   IV. 
Bar  Bridges 182 

CHAPTER  V. 
Removable  and  Replaceable  Porcelain  Fronts 187 

CHAPTER   VI. 

General  Application  of  Crown-  and  Bridge-Work 189 

Extensive  Applications  of  Crown-  and  Bridge-Work  193 

CHAPTER  VII. 
Repair  of  Crown-  or  Bridge-Work 202 


xiv  CONTENTS. 

CHAPTER  VIII. 

PAGE 

The  Hygienic  Condition  of  the  Mouth  as  affected  by  Bridge-Work  206 

CHAPTER  IX. 

Removable  and  Detachable  Bridge-Work 208 

Removable  Incisor  or  Cuspid  Crown 209 

Removable  Bicuspid  and  Molar  Attachments 212 

Connecting  Bars 216 

Construction  of  Removable  Bridge-Work 217 

CHAPTER  X. 
Removable  Plate  Bridges 225 

CHAPTER  XI. 

Special  Forms  of  Removable   and    Detachable    Bridge-Work 238 

Dr.  Winder's  Sectional  Crown  Method 238 

Dr.  Litcb's  Method 241 

Dr.  R.  W.  Starr's  Methods 243 

Dr.  Parr's  Methods 248 

Dr.  Waters's  Methods 255 

CHAPTER  XII. 
Removable  Bar-Bridges 260 

CHAPTER  XIII. 

The  Low  Bridge 266 

CHAPTER  XIV. 
Dr.  Knapp's  Methods 270 

CHAPTER  XV. 
Dr.  Melotte's  Method 275 

CHAPTER  XVI. 
Partial  Cap  and  Pin-Bridge  Methods 279 

CHAPTER  XVII. 

The  Mandrel  System 287 

Detachable  Bridge-Work , 300 

CHAPTER  XVIII. 

Porcelain  Bridge- Work 305 

Dr.  Brown's  Method 305 

CHAPTER  XIX. 

Crown-  and  Bridge- Work  combined  with  Operative  Dentistry  in 
Dental  Prosthesis 315 


CONTESTS.  XV 

PAET     IV. 

MATERIALS    AND    PROCESSES   USED    IN    CROWN-    AND    BRIDGE-WORK. 

CHAPTER  I. 

PAGE 

Plate  and  Solders 327 

CHAPTER  II. 
Porcelain  Teeth 331 

CHAPTER  III. 
Molds  and  Dies 332 

CHAPTER  IV. 
Soldering 335 

CHAPTER  V. 
Instruments  and  Appliances 337 


INTKODUCTION. 


Of  the  origin  of  the  art  of  dentistry  no  one  can  speak  with  cer- 
tainty, as  its  early  history  is  shrouded  in  the  mists  of  antiquity ; 
but  dental  operations  are  recorded  in  very  remote  times. 

References  are  made  to  the  art  in  the  writings  of  Hippocrates, 
in  the  fifth  century  B.C.  Martial,  the  Latin  poet,  in  the  first 
century  B.C.,  says  that  a  Roman  dentist  "  Cascellius  is  in  the 
habit  of  fastening  as  well  as  extracting  the  teeth."  To  Lelius 
he  says,  "You  are  not  ashamed  to  purchase  teeth  and  hair;" 
and  adds  that  "  the  toothless  mouth  of  Egle  was  repaired  with 
bone  and  ivory;"  also,  that  "  G-alla,  more  refined,  removed  her 
artificial  teeth  during  the  night." 

Horace,  in  the  same  century,  cites  the  case  of  the  "  sorceresses 
Canidia  and  Sagana  running  through  the  city  and  losing  the  one 
her  false  hair,  the  other  her  false  teeth." 

Galen,  the  celebrated  physician,  in  the  second  century  a.d., 
also  speaks  of  the  art  of  dentistry  as  being  then  practiced. 

These  early  operations  were  limited  to  the  extraction  of 
offending  teeth  and  the  replacement  of  those  which  had  been 
lost  with  substitutes  which  were  retained  in  position  by  means 
of  narrow  bands  or  ligatures  attaching  them  to  the  adjoining 
natural  teeth,  and  without  the  use  of  plates.  Crude  as  they 
were,  they  formed  the  first  expression  of  the  art  of  dentistry,  a 
beneficent  art  from  the  beginning,  in  that  it  sought  to  restore 
pathological  or  accidental  defects.  Confined  to  the  simplest 
operations,  it  existed  for  centuries,  and  then  was  apparently 

2  l 


2  INTRODUCTION. 

lost  during  the  Dark  Ages,  to  reappear  when  the  more  general 
diffusion  of  knowledge  ushered  in  the  modern  era  of  science 
and  invention. 

After  its  revival,  dentistry,  so  much  of  it  as  was  known,  was 
in  a  measure  a  secret  art,  the  practice  of  which  even  within  the 
riiemory  of  men  now  living,  and  they  not  the  oldest,  was  in- 
volved in  mystery ;  but  recent  progress  has  lifted  the  veil,  and 
dentistry,  in  the  treatment  of  the  teeth  on  correct,  scientific, 
rational  principles,  has  developed  an  art  and  a  science  which 
have  given  it  honorable  rank  among  the  professions.  In  its 
two-fold  evolution  it  has  absorbed  from  every  available  source 
whatever  would  broaden  its  science  or  perfect  its  art.  It  calls 
to  its  aid  anatomy,  physiology,  pathology,  chemistry,  thera- 
peutics, metallurgy,  sculpture,  and  mechanics,  with  each  of 
which  it  stands  in  closer  or  more  remote  relation ;  and  the 
practitioners  of  dentistry  who  have  become  the  most  eminent 
and  useful  have  been  men  of  broad  attainments  and  great 
versatility  of  talent. 

In  the  history  of  all  progress,  movements  apparently  of  a  more 
or  less  reactionary  character  are  recorded.  In  the  useful  arts 
especially  it  is  not  uncommon  to  find  a  return  to  forms  and 
methods  formerly  used  but  long  since  discarded  and  forgotten. 
So  in  dentistry  we  find  methods  of  treatment  and  modes  of 
practice  once  in  vogue  but  long  fallen  into  disuse,  revived 
with  improvements  and  modifications  that  stamp  them  as  prac- 
tically rediscoveries. 

These  movements  are  not  to  be  regarded  as  retrogressive, 
because  the  modifications  which  accompany  the  reintroduction 
of  practical  ideas  and  inventions  stamp  them  as  real  advances, 
and  indicate  clearly  that  the  cycle  of  knowledge  is  ever  widen- 
ing with  experience.  This  volume  demonstrates  how  modern 
dentistry  has  utilized  the  principles  of  some  of  the  simplest 
original  operations,  and  by  "  proving  all  things,  holding  fast  that 


INTRODUCTION.  3 

which  is  good,"  has  attained  its  present  honorable  position  in 
both  its  scientific  and  artistic  departments. 

The  history  of  dentistry  of  later  years  is,  in  brief,  a  recital  of 
progress  and  improvement.  The  medical  profession  has  officially 
recognized  it  as  closely  allied  to  medicine  by  inviting  its  rep- 
resentatives to  take  part  in  the  International  Medical  Congresses 
on  the  footing  of  professional  equality. 

Such  is  the  position  which  dentistry  has  attained.  Much  of 
the  progress  which  has  made  its  present  elevation  possible  must 
be  credited  to  the  dental  profession  of  the  United  States,  which 
has  been  justly  termed  the  cradle  of  modern  dentistry.  Here 
the  validity  of  the  idea  that  scientific  knowledge  should  form 
the  basis  of  training  for  practice  was  first  demonstrated  by  the 
successful  establishment  of  dental  schools;  here  the  first  journal 
for  the  interchange  among  dentists  of  thought  and  experience 
was  founded ;  here  the  first  association  having  for  its  object  the 
uplifting  and  upholding  of  dentistry  by  the  mutual  helpfulness 
of  its  practitioners  had  its  origin;  here,  in  a  word,  dentistry 
was  first  divorced  from  mystery,  here  it  first  passed  the  narrow 
confines  of  a  mere  handicraft  and  earned  for  itself  the  right  to 
be  classed  among  the  learned  and  liberal  professions. 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Modern  artificial  crown-  and  bridge-work  belongs  to  the 
department  of  dentistry  until  recently  termed  "mechanical,"  but 
the  judgment,  skill,  and  scientific  information  required  place  it 
far  above  ordinary  mechanical  dentistry,  which  has  sunk  to  a  low 
estate  since  the  introduction  of  vulcanite.  To  such  an  extent  has 
vulcanite,  by  reason  of  its  cheapness  and  ease  of  manipulation, 
superseded  other  materials  demanding  greater  knowledge  and 
skill  in  their  manipulation,  as  to  retard  the  higher  development 
of  prosthetic  dentistry,  and  indeed  to  divest  it,  in  the  hands  of 
those  who  depend  upon  vulcanite,  of  the  dignity  which  should 
belong  to  dentistry  as  a  profession. 

But  modern  crown-  and  bridge-work,  properly  understood 
and  properly  performed,  takes  high  rank  in  dental  art,  and 
offers  wide  scope  for  versatility  of  talent  and  inventive  genius. 
The  varied  and  complicated  cases  presenting  for  treatment  fre- 
quently suggest  to  the  expert  novel  contrivances  and  methods  of 
construction  and  application.  Successful  practice  of  crown-  and 
bridge-work  depends  upon  a  thorough  mastery  of  the  under- 
lying principles,  and  expertness  in  the  processes  involved,  gov- 
erned by  sound  judgment  and  perfect  candor.  The  interests  of 
the  patient  should  be  paramount  to  every  other  consideration, 
and  after  a  careful  examination  he  should  be  given  an  accurate 
statement  of  the  applicability  of  the  system  to  his  case,  in  re- 
spect to  usefulness,  appearance,  durability,  and  comfort,  as 
compared  with  other  processes  and  appliances  in  use. 

5 


Q  ARTIFICIAL    CROWN-  AND  BRIDGE- WORK. 

Surgical  and  mechanical  operations  of  the  most  delicate 
nature  are  required.  Nothing,  indeed,  in  dentistry  demands 
finer  manipulation.  A  practical  consideration  of  the  subject 
will  show  that  a  knowledge  of  anatomy,  pathology,  and  thera- 
peutics, and  as  well  mechanical  and  artistic  skill,  are  necessary 
to  the  correct  treatment  of  cases  and  the  proper  performance  of 
the  operations  indicated.  Among  the  principal  steps  in  an 
operation  may  be  named,  first,  the  preparatory  treatment  of  the 
natural  roots  and  teeth  for  the  final  process,  involving  the  diag- 
nosis of  present  or  probable  lesions  and  the  prescription  of 
whatever  remedial  or  prophylactic  measures  may  be  needful ; 
second,  in  crown-work,  the  adaptation  of  the  artificial  crowns  to 
the  cervical  portion  of  the  natural  roots  and  the  contiguous 
membranes,  and  the  restoration  of  the  articulation  and  the  ana- 
tomical contour;  and,  in  bridge-work,  the  selection  of  suitable 
teeth  or  roots  for  foundation  piers  or  abutments,  and  the  choice 
and  adaptation  in  constructive  practice  of  the  forms  which  will 
insure  the  highest  degree  of  stability  and  best  sustain  the  force 
of  occlusion,  thereby  avoiding  abnormal  positions  and  condi- 
tions. 

The  practice  of  crown-  and  bridge-work  by  dentists  possessing 
the  requisite  attainments  and  governed  by  correct  ethical  princi- 
ples gives  results  which  are  gradually  establishing  its  value,  re- 
moving erroneous  impressions,  and  insuring  a  wide  professional 
and  public  indorsement  of  this  important  branch  of  prosthetic 
dentistry.  Its  extraordinary  facilities  for  preserving  and  replac- 
ing teeth  are  gradually  making  for  it  the  position  in  dental  art 
which  it  merits. 


PAET   I. 

PREPARATORY  TREATMENT  OF  TEETH  AND  ROOTS  FOR 

CROWN-WORK. 


PREPARATORY  TREATMENT  OF  TEETH  AND 
ROOTS  FOR  CROWN-WORK. 

Preparatory  treatment  of  teeth  and  roots  for  crown-work 
includes,  in  addition  to  the  shaping  required  to  fit  them  for  the 
reception  of  the  crowns,  the  bringing  about  of  the  healthiest 
possible  condition  in  the  teeth  and  roots  and  the  adjacent  parts, 
as  the  cure  of  existing  lesions,  the  removal  of  calculus  where 
necessary,  and  the  adoption  of  such  measures  as  shall  prevent 
the  recurrence  of  old  troubles  or  the  inception  of  new. 

Notwithstanding  all  that  advanced  knowledge  of  therapeutical 
agents  and  skill  in  their  use  permit,  there  are  many  teeth  and 
roots  which  cannot  be  rendered  suitable  for  the  successful  appli- 
cation of  crown-  or  bridge-work.  Roots  which  are  permeated 
and  softened  by  decay,  exposed  or  loosened  from  absorption  of 
the  gums  and  alveoli,  or  affected  with  irremediable  disease  of 
the  investing  membranes,  should  be  thus  classed.  Cases  in 
which  abscess  with  necrosis  has  extensively  impaired  the  walls 
of  the  alveoli  are  equally  intractable. 

Experience  shows  that  the  results  in  this  department  of  den- 
tistry depend  largely  upon  diathesis  or  constitutional  tendency 
and  upon  the  attention  given  to  the  preservation  of  the  health 
of  the  mouth ;  and  these  conditions  should  be  carefully  estimated 
in  the  selection  of  a  system  of  treatment  and  the  method  of  its 
application. 


CHAPTER    I. 

THE  PULPS   OF  TEETH— THEIR   PRESERVATION  OR  DEVITALI- 
ZATION—PULP-CAPPING. 

The  preservation  of  the  vitality  of  the  pulps  of  the  teeth  is  a 
matter  of  as  much  importance  in  connection  with  crown-  and 
bridge-work  as  in  an}-  other  class  of  operations,  though  the 
excision  of  natural  crowns  for  the  purpose  of  utilizing  the  roots 
as  abutments  for  bridge-work  is  extensively  practiced,  and  is 
defended  on  the  theory  that  the  vitality  of  the  dentine  is  main- 
tained by  the  cementum  after  the  extirpation  of  the  pulp.1 

Dr.  C.  F.  "W.  Bodecker,  discussing  the  subject  of  the  "Dis- 
tribution of  Living  Matter  in  Human  Dentine,"  says,2 — 

"1st.  The  dentinal  canaliculi  are  excavations  in  the  basis- 
substance  of  the  dentine,  each  containing  in  its  center  a  fiber  of 
living  matter.  Besides  the  dentinal  canaliculi,  there  exists  an 
extremely  delicate  net-work  within  the  basis-substance  of  the 

1Dt.  J.  L.  Williams  says,  "The  life  and  vitality  of  the  cementum  remain  in- 
tact and  uninjured,  and  even  the  dentine  may,  and  undoubtedly  does,  retain  a 
certain  amount  of  vitality,  for  something  analogous  to  a  healing  process  takes 
place  at  the  ends  of  the  broken  fibrillar  next  to  the  pulp-chamber,  and  by  one 
of  those  wonderful  provisional  conditions  which  we  so  often  meet  with  in  the 
economy  of  the  animal  kingdom  nature  reverses  or  changes  the  origin  of  nutri- 
tive supply,  and  the  material  for  maintaining  the  continued  vitality  of  the  den- 
tine comes  through  the  cementum." 

He  further  says,  "  Every  practicing  dentist  has  observed  that  a  tooth  which  is 
removed  from  contact  with  the  fluids  of  the  mouth  changes  color.  This  change 
in  color  is  largely  the  result  of  the  evaporation  of  the  water  from  the  organic 
portion  of  the  tooth.  Now,  if  the  apical  foramen  of  such  a  tooth  be  closed,  and 
the  tooth  be  then  placed  in  water,  or  preferably,  glycerin  and  water,  in  a  short 
time  it  will  regain  nearly  its  original  color,  and  at  the  same  time  it  will  be  found 
that  it  has  increased  in  weight.  This  means,  of  course,  that  the  entire  tooth  has 
absorbed  from  the  surface  a  certain  quantity  of  the  fluid,  and  this  fluid  has  pene- 
trated every  part  of  the  solid  structure  of  the  tooth.  Will  any  one  doubt,  with 
these  facts  in  view,  that  when  the  tooth  is  in  position  in  the  jaw,  and  surrounded 
by  all  the  delicate  adjustments  furnished  by  nature,  there  may  be  a  circulation 
of  nutrient  fluids  throughout  the  entire  root  after  the  removal  of  the  pulp?" 

It  is  difficult  to  understand  how  a  saturation  can  be  compared  to  an  infiltration 
controlled  by  vital  circulation. — G.  E. 

2  Dental  Cosmos,  vol.  ix,  page  656. 
10 


Plate  II. 


M 


, 


J* 


■  \     ! 


Plate  III. 


w% 


- 


t 


From  Specimens  made  by  M.  H.  Fletcher,  M.  I).,  Dentist.     Cincinnati,  Ohio. 


THE  PULPS  OF  TEETH.  H 

dentine,  into  which  innumerable  offshoots  of  the  dentinal  fibers 
pass.  Although  we  cannot  trace  the  living  matter  throughout 
the  whole  net-work  in  the  basis-substance,  evidently  owing  to  its 
delicacy,  we  are  justified  in  assuming  that  not  only  the  dentinal 
canaliculi,  but  the  whole  basis-substance  of  the  dentine  is  also 
pierced  by  a  delicate  net-work  of  living  matter.  The  living 
matter  of  the  dentine  is  in  direct  union  with  that  of  the  proto- 
plasmic bodies  of  the  pulp,  of  the  cementum,  and  of  the  enamel. 

"  2d.  The  cementum,  as  wrell  as  ordinary  bone,  is  provided 
with  lacuna?  and  canaliculi.  The  lacunas  contain  nucleated 
protoplasmic  bodies,  and  the  canaliculi  hold  offshoots  of  the 
living  matter  of  the  protoplasm.  The  whole  basis-substance  of 
the  cementum  is  traversed  by  a  delicate  net-work,  which  in  all 
probability  contains  living  matter,  though  this  is  traceable  only 
in  its  thorn-like  projections  from  the  periphery  of  the  proto- 
plasm and  its  larger  offshoots.  The  living  matter  of  the  cementum 
is  uninterruptedly  connected  with  that  of  the  periosteum,  and  continuous 
with  that  of  the  dentine,  either  through  intervening  protoplasmic  bodies 
in  the  interzonal  layer,  or  directly  with  the  dentinal  fibers." 

This  distribution  and  relative  connection  of  living  matter  as 
described  refers  to  an  existing  state  of  perfect  vitality  of  all  the 
parts.  When  the  pulp  loses  its  vitality,  an  entirely  different 
condition  results.  The  tubuli  are  then  deprived  of  vital  circula- 
tion, except  along  the  line  of  the  outer  portion  of  the  dentine, 
where,  in  the  interzonal  layer,  the  fibrillar  anastomose  with  the 
living  matter  of  the  cementum.  The  vitality  supported  by  this 
anastomosis  is  almost  entirely  confined  to  this  part,  the  nutrient 
supply  being  insufficient  to  assume  the  functions  of  the  pulp  and 
maintain  circulation  in  the  main  body  of  the  dentine.  (See 
Plates  I,  II,  III.) ' 

1  Plata  I. — Longitudinal  section  of  the  root  of  a  superior  bicuspid,  at  junction 
of  dentine  with  cementum.  C,  cementum  ;  D,  dentine  ;  I,  interzonal  layer  ;  L, 
lacunaj  of  cementum.     X  175. 

Plate  II. — A  Held  taken  from  Plate  I  in  position  marked  A.  L,  lacunae  of 
cementum;  C,  canaliculi  of  dentine;  I,  interzonal  layer.     X  210. 

Plate  III.  —  A  field  taken  from  Plate  I  in  position  marked  B.  L,  L,  L, 
lacuna'  of  cementum  ;  I,  interzonal  layer;  D,  dentinal  tubes  and  their  nearest 
approach  to  the  lacuna'.  210. 

A  study  of  these  plates  demonstrates  the  limited  nature  of  the  anastomosis  of 
the  fibers  of  living  matter  of  the  dentine  and  cementum. 


12  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

Chemical  analysis  of  the  dentine  shows  that  the  organic 
matter,  consisting  principally  of  the  fibrilla?,,  exists  in  the  pro- 
portion of  nearly  28  per  cent,  to  72  per  cent,  of  lime-salts.1 

When  the  pulp  has  been  removed,  the  devitalized  fibrilhe 
still  remain,  and  are  capable  of  generating  septic  gases  which 
will  exert  an  influence  in  producing  irritation  of  the  cementum 
and  pericementum,  no  matter  how  thoroughly  the  root-canal 
has  been  filled  and  the  foramen  closed.  An  examination  of  the 
investing  membranes  of  pulpless  teeth  generally  shows  the 
existence  of  abnormal  conditions,  b}^  which  their  firmness  is  to 
some  extent  impaired,  their  susceptibility  to  acute  inflammation 
increased,  and  their  reliability  as  foundations  for  crown-  or 
bridge-work  greatly  lessened  when  compared  with  teeth  which 
have  living  pulps. 

In  crown-work,  facilities  are  afforded  for  the  preservation  of 
pulps  in  the  posterior  teeth.  Thus,  in  a  case  verging  on  expos- 
ure, only  partial  removal  of  the  decay  is  usually  necessary,  as, 
when  the  operation  is  completed,  the  natural  crown  will  be 
hermetically  inclosed  by  the  artificial  one.  In  bridge-work, 
proper  methods  of  practice  permit  the  anterior  teeth  to  be  used 
as  abutments  without  the  extirpation  of  their  pulps  or  the 
excision  of  their  crowns. 

Extirpation  is  demanded  for  those  pulps  whose  permanent 
preservation  cannot  be  placed  beyond  doubt,  as  failure  involves 
more  serious  consequences  in  crown-  and  bridge-work  than  in 
filling-operations.  The  lesions  of  the  pulp  which  seem  to  re- 
quire its  extirpation,  according  to  the  generally  expressed  opinion 
on  the  subject,  are  exposure  with  hypertrophy  or  rupture  of  the 
pulp-sac,  congestion,  and  pulpitis  which  does  not  yield  promptly 


1  According  to  Berzelius  and  Bibra,  dentine  consists  of 

Organic  matter  (tooth-cartilage)  ........     27.61 

Fat 40 

Calcium  phosphate  and  fluoride   ........     66.72 

Magnesium  phosphate  .........       1.18 

Calcium  carbonate        .         .         .         .         .         .         .         .         .         .3.36 

Other  salts    ............         .83 

Age  lessens  the  proportion  of  living  matter  and  increases  the  percentage  of 
lime-salts. 


THE  PULPS  OF  TEETH.  13 

to  remedial  treatment.  Pulps  actually  exposed  by  decay  are 
seldom  found  in  a  normal  condition  otherwise,  and  they  are 
only  rarely  proper  or  hopeful  subjects  for  remedial  treatment. 
Atrophy  of  the  membrana  ebori&,  or  investing  membrane,  which 
comprises  the  layer  of  odontoblasts,  usually  exists  at  the  part 
exposed,  and,  as  any  subsequent  calcification  must  depend  on 
the  activity  of  the  odontoblasts,  it  is  evident  that  the  existence 
of  the  condition  referred  to  affords  a  strong  argument  against 
the  advisability  of  capping  pulps  in  cases  of  extensive  or  even 
slight  exposure.  The  difficulty  of  securing  a  condition  of  asepsis 
of  the  exposed  and  diseased  parts  so  perfect  as  to  assure  them 
against  the  invasion  of  micro-organisms  subsequent  to  capping 
is  an  additional  argument  against  the  operation. 

Pulps  which  are  in  a  normal  condition,  still  protected  by  a 
layer  of  even  decomposed  or  partly  decomposed  dentine,  usually 
admit  of  successful  treatment.  In  such  cases,  the  decayed  dentine 
may  be  excavated  from  the  side  walls  of  the  cavity,  but  that  in 
the  region  of  the  pulp  should  be  only  superficially  removed ;  in 
some  cases,  this  portion  may  be  allowed  to  remain  undisturbed. 

Pulp-Capping. — The  operation  of  capping  a  pulp  should  in- 
clude, as  a  necessary  precaution  against  subsequent  irritation, 
the  thorough  disinfection  of  any  remaining  decomposed  den- 
tine. An  excellent  method  of  securing  disinfection  is  by  first 
thoroughly  washing  the  cavity  several  times  with  tepid  water 
thrown  gently  from  the  large  point  of  a  syringe  around  the 
sides  of  the  cavity;  then,  taking  measures  to  prevent  the 
entrance  of  saliva,  wiping  the  cavity  with  absorbent  cotton 
and  passing  over  its  surface  a  light  current  of  hot  air  from  a 
hot-air  syringe.  The  heat  should  be  sufficient  to  cause  sour- 
discomfort  to  the  patient,  but  not  enough  to  produce  irritation 
of  the  pulp.  The  dried  cavity  is  then  immediately  saturated 
with  wood  creasote1  previously  warmed2  to  the  normal  tempera- 
ture of  the  body  by  holding  the  pellet  of  cotton  on  which  it  is 

lA  refined  pure  wood  creasote,  such  as  is  prepared  for  dental  u.~es,  is  the  best 
for  this  purpose.  Carbolic  acid,  alone  or  in  combination  with  oil  of  cloves,  is 
preferably  used  by  some  operators. 

2  Thermal  shock  to  the  pulp  is  as  unwarranted  from  the  application  of  cold 
creasote  as  if  produced  in  any  other  manner. 


14  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

•applied  over  the  flame  of  a  lamp  for  a  moment.  The  creasote 
relieve?  any  pain  caused  by  the  evaporation  of  moisture,  and 
disinfects  and  sterilizes  any  decomposed  matter  in  proximity  to 
the  pulp.  The  object  of  the  application  of  the  creasote  having 
been  accomplished,  it  may  then  be  removed  as  far  as  possible. 
To  this  end  the  cavity  should  first  be  wiped  with  absorbent 
cotton,  and  hot  air  again  introduced  to  evaporate  the  creasote 
sufficiently  to  give  a  dry  appearance  to  the  surface.  This  second 
application  of  hot  air,  owing  to  the  effect  of  the  creasote,  will 
cause  very  little  or  no  pain. 

This  method,  if  practiced  early  in  the  preparation  of  the  cavity, 
will  be  found  to  considerably  obtund  sensation,  and,  through  the 
dryness  secured,  to  materially  facilitate  the  removal  of  the  de- 
composed dentine.  A  reasonable  amount  of  the  decayed  por- 
tion should  be  cut  away,  as  it  lessens  the  difficulty  of  proper 
disinfection.  For  excavating  in  the  region  of  the  pulp-chamber, 
spoon-shaped  excavators  should  be  used  invariably. 

The  disinfected  dentine  over  the  pulp  is  then  capped  with 
oxyphosphate.  For  this  purpose  the  cement  should  be  mixed 
soft.  Tlie  proper  quantity  is  then  applied  to  one  side  of  the 
cavity  and  brought  over  against  the  bottom  in  such  a  way  as  not 
to  inclose  air  between  the  cement  and  the  surface,  or  cause  the 
slightest  pressure  upon  the  pulp.  This  is  an  operation  requiring 
careful  and  delicate  manipulation.  Properly  performed,  it  is 
preferable,  in  most  cases,  to  protecting  the  part  with  a  plate  or 
cap,  either  metallic  or  non-metallic,  fitted  to  the  bottom  of  the 
cavity  to  avoid  pressure  of  the  cement;  or  to  the  use  of  concave 
caps  filled  with  the  cement;  as,  owing  to  the  adhesive  character 
of  oxyphosphate  of  zinc,  pressure  from  encompassed  air  is  apt 
to  occur  frequently  when  the  cap  is  adjusted  in  position. 

If  there  is  any  apprehension  of  acid  reaction  from  the  oxy- 
phosphate affecting  the  pulp,  the  bottom  of  the  cavity  can  be 
first  covered  with  a  little  dry  oxide  of  zinc  or  chloro-gutta-percha, 
the  chloroform  being  evaporated  in  the  latter  case  with  the  hot- 
air  syringe.1     The  creasote  by  its  presence  and  action  on  the  sur- 

xAcidity  of  oxyphosphate  cement  arises  from  the  use  of  too  much  acid  in  pro- 
portion to  the  oxide,  from  lack  of  thorough  manipulation,  or  from  unsuitable 
<>\ide  of  zinc.     (See  article  on  "  Cementation.'') 


THE   PULPS  OF  TEETH.  15 

face  of  the  dentine  forms  the  only  really  necessary  barrier  to  acid 
reaction,  if  the  oxyphosphate  of  zinc  is  suitably  constituted,  cor- 
rectly compounded,  and  properly  used. 

Pulp-capping,  when  necessary,  should  precede  any  other  oper- 
ation, and  no  subsequent  procedure  is  admissible  until  the  success 
of  that  operation  is  assured,  the  time  allowed  for  this  purpose 
being  governed  by  the  diagnosis  of  each  case.  A  non-vital  con- 
dition of  the  pulp  in  one  root  of  a  tooth  contraindicates  any  at- 
tempt to  preserve  it  in  any  of  the  other  roots,  in  connection  with 
crown-  and  bridge-work.  The  rubber-clam,  when  its  use  is  prac- 
ticable, will  be  found  a  material  aid  in  difficult  pulp-capping 
operations. 


CHAPTER  II. 

DEVITALIZATION   OF   THE   PULP. 

In  preparation  for  crown-work  two  methods  of  devitalization 
are  practiced :  the  heroic, — instantaneous  devitalization,  or  ex- 
tirpation,— and  gradual  devitalization  by  arsenical  treatment. 

Instantaneous  devitalization  can  be  accomplished  by  first  admin- 
istering to  the  patient  sufficient  nitrous  oxide  to  produce  partial 
anesthesia,  then  with  a  drill  quickly  opening  into  the  pulp- 
chamber,  and  lacerating  the  pulp  well  up  the  canal  with  a  probe 
or  smooth  broach.  Instantly  afterward  a  pellet  of  cotton,  satu- 
rated with  carbolic  acid,  is  forced  up  the  canal,  and,  if  possible, 
left  until  the  next  day,  when  the  pulp  will  be  found  in  a  coagu- 
lated mass  that  is  easily  removed  entire. 

Devitalization  of  the  pulp  as  just  described  is  practicable  only 
in  teeth  in  normal  condition.  In  acute  inflammation,  after  lacer- 
ation of  the  pulp,  warm  water  should  be  gently  injected  into  the 
pulp-chamber,  and  sedative  agents  then  applied.  Subsequent 
treatment  should  be  such  as  will  complete  the  devitalization  and 
extirpation  of  the  pulp. 

In  cases  of  actual  exposure  of  the  pulp,  the  rubber-dam  can 
be  applied,  the  exposed  section  obtunded  with 
IG-  !•  hydrochlorate  of  cocaine,  either  the  moistened 

crystal  or  a  very  strong  solution,  and  as  soon 
as  its  action  is  manifested  the  pulp  then  injected 
with  the  solution  and  extirpated. 

Excision  of  the  crown  and  instantam  ous  extir- 
CIS  pation  of  the  pulp  is  practiced  by  many  as  follows  : 

Two  parallel  grooves  are  cut  opposite  to  each 
other,  through  the  enamel,  deep  into  the  den- 
tine, one  on  the  labial  portion  of  the  tooth  and 
the  other  on  the  palatal  wall,  close  to  the  gum,  with  a  rapidly 
revolving  corundum  or  rubber  and  corundum  disk  (Fig.  1).    Then 

16 


DEVITALIZATION  OF  THE  PULP. 


17 


Fio.  2. 


Fig.  3. 


with  excising  forceps,  the  cutting-edges  of  which  are  inserted  in 
these  grooves,  the  crown  is  quickly  severed  from  the  root  (Fig. 
2).  The  pulp  either  adheres  to  the  excised  crown,  leaving  the 
canal  empty,  or  remains  in  the  root,  fully  exposed.  In  the  latter 
case,  a  pointed  piece  of  orange  wood,  previously  cut  to  fit  the 
canal,  and  saturated  with  carbolic  acid,  is  quickly  driven  with  a 
blow  into  the  pulp  toward  the  apex  of  the  root  (Fig.  3).  When 
the  wood  is  withdrawn,  the  pulp  usually  adheres  to  it ;  if  not, 
the  wood  is  instantly  reinserted,  cut  off  and  drilled  out  with  the 
pulp,  using  Gates-Glidden  drills  in  the  upper 
portion  of  the  canal.  In  this  operation,  it  is 
claimed,  only  trilling  pain  is  experienced  by 
the  patient,  as  the  pulp  is  paralyzed  by  shock 
in  the  excision  of  the  crown,  or  by  being 
forced  upward  toward  the  foramen  and 
against  the  walls  of  the  canal. 

The  objections  to  this  opera- 
tion are,  that  if  the  pulp  is  not 
successfully  extracted  entire 
with  the  wood  the  canal  becomes 
filled  with  clotted  blood,  which 
is  difficult  to  remove  from  the 
extreme  end  ;  also  that  the  root 
and  socket  are  jam  d  by  the  for- 
ceps in  excising  the  crown ;  but, 
expertly  performed,  it  is  advantageous  in  many  cases,  though  it 
must  be  confined  to  pulps  in  normal  condition. 

Devitalization  with  Arsenious  Acid. — The  methods  of  devitalizing 
previously  described  are  applicable  principally  to  the  pulps  of 
incisors  and  cuspids.  In  the  posterior  teeth,  which  do  not  so 
well  permit  the  heroic  treatment,  recourse  is  had  to  arsenious 
acid,  notwithstanding  the  numerous  objections  to  its  use.  Two 
theories  as  to  the  mode  of  its  action  in  devitalizing  are  widely 
entertained:  First,  that  by  producing  irritation  of  the  pulp  it 
causes  its  expansion,  which  stops  circulation  by  strangulation  at 
the  foramen  ;  the  other  is  thrombosis.1 

This  theory  of  thrombosis  accounts  for  the  gradual  devitaliza- 


1  See  Dr.  L.  C.  Ingersoll's  "  Dental  Science,  Questions  and  Answers,"  page  9F>. 

3 


Is  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

tion  of  the  pulp  toward  the  foramen,  and  is  very  likely  the  true 
explanation. 

Whatever  the  action  of  arsenic  on  the  pulp  may  be,  it  always 
causes  an  infiltration  of  the  tubuli  of  the  dentine  with  certain 
constituents  of  the  blood,  probably  the  liquor  sanguinis.  The 
residue  of  the  infiltration,  after  the  devitalization  of  the  pulp, 
remains  in  the  tubuli,  and  increases  the  difficulty  of  producing 
an  aseptic  condition  of  the  dentine.  It  is  asserted  that  in  some 
cases  arsenic  affects  the  vitality  of  the  cementum,  while  after 
instantaneous  extirpation  of  the  pulp,  when  arsenic  is  not  used, 
vitality  is  assured. 

Practical  experience  shows  that  usually  instaut  devitalization 
or  extirpation  is  the  most  satisfactory  in  general  and  final  re- 
sults. Arsenic,  when  used,  should  be  applied  directly  to  the 
pulp  in  the  smallest  quantity  possible  to  effect  its  devitalization, 
and  securely  sealed  in  the  cavity. 

In  cases  of  non-exposure,  requiring  its  application,  a  small 
opening  into  the  pulp-chamber  should  be  made.  This  can  be 
accomplished  with  but  little  pain  to  the  patient  with  a  very 
small,  sharp,  spear-headed  drill,  rapidly  revolved  by  the  engine. 
The  drill  should  be  held  steadily  under  gentle  pressure  at  one 
point  in  the  line  of  the  intended  exposure,  until  the  pulp  is 
slowly  and  gradually  reached,  and  not  suddenly  punctured  with 
the  drill-point.  The  point  of  the  drill  should  be  occasionally 
removed  and  dipped  in  carbolic  acid,  or  a  saturated  solution  of 
cocaine  in  glycerin,  during  the  operation. 

The  use  of  arsenic,  combined  with  agents  which  are  non- 
coagulants  of  albumen,  is  recommended  in  preference  to  com- 
bining: it  with  creasote  or  carbolic  acid.  Dr.  Harlan's  method 
is  to  apply  an  anodyne,  such  as  wine  of  opium,  for  a  minute  or 
two,  and  then  the  following  paste : 

R — Arsenious  acid,  ^i; 

Muriate  of  cocaine,  gii; 

Lanolin  in  quantity  sufficient  to  make  a  stiff  paste. 

The  application  should  be  kept  in  position  no  longer  than  is 
necessary  to  effect  the  devitalization  of  the  pulp,  twelve  to  forty- 
eight  hours  being  sufficient  for  the  purpose.  The  pulp  is  then 
punctured,  a  saturated  solution  of  tannin  in  glycerin  applied 


DEVITALIZATION  OF  THE  PULP.  19 

and  securely  sealed  in  the  cavity,  and  the  patient  dismissed  for 
several  days.  At  the  end  of  that  time  the  pulp  can,  as  a  rule,  be 
removed  entire.  The  rubber-dam  should  be  applied,  the  saliva 
entirely  excluded,  and  absolute  alcohol  instead  of  water  used  in 
the  treatment.1  When  creasote  or  carbolic  acid  is  used  in  com- 
bination with  arsenic,  the  same  method  of  subsequent  treatment 
may  be  practiced. 

1  See  Dental  Cosmos,  vol.  xxiiii,  page  138. 


Plate  IV. 


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CHAPTER    III. 


PULPLESS   TEETH— PREPARATION    OF    ROOT-CANALS— THEI R 
TREATMENT,  DISINFECTION,  AND  FILLING. 

The  treatment  of  pulpless  teeth  or  roots  consists  in  as  thorough 
a  performance  as  possible  of  the  following  operations : 

1st.  Removal  of  the  contents  of  the  canals. 

2d.  Disinfection  of  the  root-canals  and  the  dentine,  and  the 
establishment  of  permanent  aseptic  conditions  by  mummification 
of  the  contents  of  the  tubuli. 

3d.  Closure  of  the  apical  foramen. 

Preparation  of  Root-Canals. — A  knowledge  of  the  usual  posi- 
tions of  the  root-canals  in  the  different  teeth  is  essential  for  a 
generally  successful  performance  of  this  operation,  which  is 
greatly  facilitated  by  the  ease  with  which  direct  FlG  4 

access  to  the  root-canals  is  obtained  in  crown- 
work.  (See  Plate  IV.)1  In  the  anterior  teeth, 
the  removal  of  the  coronal  section  directly  ex- 
poses the  pulp-cavity.  In  bicuspids  and  molars, 
for  all-gold  crowns,  the  leveling  of  the  occluding 
surface  (see  Fig.  4)  and  removal  of  a  portion  of 
the  >ide  most  involved  by  decay  should  be  pre- 
liminary. An  opening  is  first  made  into  the  cen- 
ter of  the  pulp-chamber  in  a  line  with  the  root- 
canals  sufficient  to  give  free  and  direct  access  to 
them,  and  any  remaining  portion  of  the  pulp  re- 
moved with  broaches.  The  canals  are  then,  guided  by  fre- 
quent explorations  with  a  fine  probe,  carefully  enlarged  with 
Gates-Glidden    drills    (Fig.    5).     At   least   three    sizes — large. 

1  Plate  IV. — Figs.  1  and  2  represent  the  superior  and  inferior  teeth  in  trans- 
verse section  through  the  base  of  the  pulp-chamber  in  the  crown,  showing  the 
entrance  to  the  root-canals. 

Figs.  3  and  4  represent  the  superior  and  inferior  teeth  in  transverse  section 
through  the  root-canals  a<  they  diverge  from  the  pulp-chamber. 

aa,  bb,  cc,  dd,  ff,  dd,  and  &>.,  Figs.  3  and  4,  show  the  relative  shapes,  whether 
circular,  oval,  or  flattened,  of  the  root-canals  in  the  teeth  they  severally  represent. 

21 


Sectional  view  of 

an  inferior  molar 
decayed  on  the  pos- 
terior approximal 
side.  A,  the  line  to 
which  the  crovrn 
should  be  removed 
to  facilitate  en- 
trance to  the  pulp- 
chamber. 


22 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


Fig.  5. 


medium,  and  small — of  drills  each  for  the  right-angle  and  the 
direct  hand-piece  are  required.  Very  little,  if  an}',  pressure 
should  be  put  upon  them  when  in  motion,  as  they  will  move 
forward  of  themselves.  Under  pressure  the 
formation  of  a  false  passage  in  a  curved  root 
is  possible,  or  the  small  drill  might  be  broken 
off  or  forced  through  the  apical  foramen 
with  disastrous  consequences,  where  alveolar 
abscess  did  not  exist.  Neither  should  drills 
be  forced  into  canals  closed  by  calcification, 
nor  into  the  canal  beyond  the  line  of  the  zone 
of  cementum  at  the  end  of  the  root,  nor 
through  a  constriction  which  a  fine,  flexible 
probe  cannot  enter,  nor  around  a  curve  sharp 
enough  to  be  unsafe  to  pass.  A  slight  pain  is  usually  experi- 
enced when  they  enter  the  zone  of  sensibility  formed  by  the 
cementum  which  composes  the  end  of  the  root,  of  the  slightest 
symptom  of  which  the  patient  should  be  instructed  to  instantly 
inform  the  operator.  The  probe-like  points  of  these  drills  do  n<  >t 
cut,  but  simply  guide  the  drills  and  confine  them  to  the  line  of  the 
canal.  They  should  be  gently  given  a  slight  forward  and  back- 
ward motion  in  the  canal,  and  treated  more  as  reamers  than 
drills.  The  occasional  quick  withdrawal  of  the  drill  from  the 
canal  during  the  process  of  drilling  will  aid  removal  of  the  debris. 
The  depth  to  which  a  canal  may  be  enlarged  or  reamed  is  regu- 
lated by  its  actual  length  and  the  above-mentioned  conditions, 
and  the  diameter  of  the  enlargement  by  the  shape  and  dimen- 
sions of  the  root.  The  use  of  these  drills  is  condemned  by 
some  for  reasons  attributable  to  their  careless  or  improper  em- 
ployment, but  they  are  indorsed,  in  experienced  hands,  for  their 
adaptability  to  the  work  under  consideration.  They  should 
be  frequently  sharpened  with  a  suitably  shaped  piece  of  Arkansas 
stone.  The  Palmer  root-canal  excavator  also  will  frequently  be 
found  serviceable  to  open  up  a  canal  and  enlarge  it  in  accord- 
ance with  its  original  shape. 

The  reaming  of  a  root-canal  not  only  simplifies  the  operation 
of  filling,  but  also  opens  up  the  ends  of  the  tubnli  and  facilitates 
the  permeation  of  antiseptic  agents. 


TREATMENT  OF  PULPLESS  TEETH. 


23 


Treatment  and  Disinfection. — Pulpless  teeth  are  presented  for 
treatment  in  one  of  the  four  following  conditions : 

1.  Where  a  healthy  or  non-putrescent  pulp  has  just  been  ex- 
tirpated from  the  canals. 

2.  "Where  on  opening  into  the  pulp-chamber  it  is  found  empty 
and  dry,  with  the  pulp  mummified  or  calcified  in  the  root-canals, 
and  the  root  externally  in  a  healthy  condition. 

Fig.  6. 


3.  Where  the  pulp  is  found  in  a  putrescent  condition. 

4.  Where  alveolar  abscess  is  present  and  a  septic  condition  of 
the  canals  and  dentine  exists. 

In  the  first  and  second  classes,  the  treatment  should  be  directed 
to  assuring  a  continuance  of  the  existing  aseptic  condition,  and 

Fin.  7. 


as  immediate  as  possible  filling  of  the  canal;  in  the  third  and 
fourth  classes,  to  bringing  about  an  aseptic  condition  by  disin- 
fection and  sterilization,  and  making  certain  of  its  future  main- 
tenance, including  incidentally  the  cure  of  any  existing  disease 
of  the  external  membranes  or  of  the  alveolus. 


24 


ARTIFICIAL  CROWN-  AND  BRIDQE-WORK. 


Fig.  8. 


Fig.  9. 


The  root-canal  having  been  properly  opened  up,  and  its  con- 
tents removed,  if  necessary,  it  should  be  washed  out  with  abso- 
lute alcohol,  or,  in  case  the  pulp  has  been  long  devitalized,  with 
warm  water,  and  then  with  peroxide  of  hydrogen,  after  which 
it  should  be  temporarily  filled  with  cotton. 

(In  the  treatment  of  the  first  and  second  classes,  water  and 
saliva  should  be  excluded  from  the  pulp-chamber,  as  also  in  the 
third  and  fourth  classes  as  soon  as  asepsis  is  effected.) 

The  mouth  is  then  properly  protected  with  napkins,  or  if  prac- 
ticable the  rubber-dam  is  applied,  and  the  cavity  dried  with  ab- 
sorbent cotton.  A  current  of  hot  air  is  next  introduced  into  the 
pulp-chamber  by  an  ordinary  (Fig.  6)  or  a  Richmond  (Fig.  7) 
hot-air  syringe,  at  a  temperature  higher,  as  it  leaves  the  nozzle, 
than  is  comfortable  for  the  finger. 
This  heats  any  part  of  the  crown  re- 
maining, and  the  lower  portion  of  the 
root.  A  silver  probe,  tapered  as  fine  as 
a  broach  at  the  point,  and  connected  with 
an  oval-shaped  mass  of  silver  or  copper 
(Fig.  8)  which  has  been  heated  to  a  dull 
red  heat,  is  then  introduced  into  the 
root-canal  (Fig.  9).  As  silver  possesses 
remarkable  properties  as  a  thermal  con- 
ductor, the  heat  is  transmitted  to  the 
point  of  the  probe  very  rapidly.1  The 
probe  being  inserted  as  far  as  possible 
up  the  canal,  the  patient  is  directed  to 
raise  the  hand  as  a  signal  should  the 
heat  cause  pain,  when  the  probe  must  be 
moved  up  and  down,  or  withdrawn  for 
a  moment.  This  procedure,  following 
the  previous  application  of  hot  air  with  the  syringe,  evaporates  the 

1  As  a  test  of  the  thermal  conductivity  of  silver,  heat  the  oval  portion  of  this 
instrument  to  a  dull  red  heat,  and  place  the  broach-like  point  of  the  probe  in  a 
little  water  on  the  end  of  a  cork.  The  water  will  boil  and  evaporate  in  a  few 
seconds.  Several  methods,  more  or  less  effective  and  complicated,  have  been  in- 
troduced to  accomplish  the  same  end,  but  they  are  less  reliable  and  convenient 
than  that  detailed. 


TREATMENT  OF  PULPLESS  TEETH.  25 

moisture  and  any  gases  present  in  the  root-canals  and  the  open 
ends  of  the  tubuli.  The  heat  also  acts  as  a  germicide,  and  it 
may  be  applied  so  intense  as  to  carbonize  any  organic  matter 
the  instrument  touches.  A  portion  of  the  carbonized  organic 
matter  will  adhere  to  the  point  and  be  removed  with  it. 

The  .suitability  of  various  antiseptics  to  the  needs  in  treating 
tooth-structures,  their  effectiveness  and  permanency  when  so 
used,  singly  or  in  combination,  are  subjects  on  which  great  di- 
versity of  opinion  exists,  and  which  have  of  late  been  made  the 
object  of  .clinical  study  and  scientific  investigation  and  discus- 
sion. Many  antiseptics  in  common  use,  being  coagulants  of 
albumen,  obstruct  the  dentinal  tubuli,  and  consequently  limit 
their  own  diffusibility  throughout  the  dentine.  Carbolic  acid, 
creasote.  and  like  agents  are  hems;  discarded  for  this  and  other 
reasons,  among  which  may  be  named  their  inefticienc}'  to  ac- 
complish the  end  sought  and  their  eventual  absorption  from  the 
dentine.  Recent  investigations  and  present  methods  of  practice 
give  preference  to  such  antiseptics  as  are  non-coagulative  in 
their  action.  Of  this  character  are  the  essential  oils  (many  of 
which,  according  to  Miller,  Harlan,  and  others,  possess  anti- 
septic power  much  greater  than  has  been  commonly  attributed  to 
them),  peroxide  of  hydrogen,  acidulated  solutions  of  bichloride 
of  mercury,  and  various  preparations  of  iodine,  all  of  which 
exert  chemical  action  and  retain  antiseptic  properties  for  a  great 
length  of  time. 

While  the  dentine  is  in  the  heated  and  dried-out  condition 
above  described,  it  should  be  saturated  with  antiseptics.  The 
acidulated  bichloride  of  mercury  (3-^  solution)  maybe  first  used 
for  the  purpose.  The  canals  can  be  agaiu  heated  and  dried,  and 
oil  of  cloves,  oil  of  cinnamon,  or  oil  of  eucalyptus,  in  a  saturated 
solution  with  iodoform  or  aristol,  applied.  The  oil  of  cloves 
will  be  found  more  decidedly  sedative  in  its  action  than  the 
other> ;  tor  this  reason  it  is  recommended  in  the  preliminary 
treatment  of  such  cases  as  may  suggest  its  use. 

The  dressing  of  root-canals  is  best  performed  with  the  aid  of 
a  flexible  rectangular  probe,  such  as  the  How.  The  form  of 
this  instrument  permits  libers  of  cotton  to  be  easily  wound 
around  it  lengthwise  and  over  its  point  in  one  connected  mass. 


26  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

When  the  cotton  is  introduced  in  the  canal,  it  is  retained  on  and 
carried  forward  by  the  instrument,  which,  when  withdrawn, 
leaves  the  cotton  in  position  in  the  canal  in  the  form  of  a  cone 
or  tampon  that  will  favor  the  escape  of  gases,  and  it  may  still  be 
easily  removed  at  any  time.  After  one  or  more  treatments  in 
the  manner  described,  in  which,  if  interspersed  by  intervals  of 
time,  the  antiseptic  agents  must  be  hermetically  sealed  in  the 
cavity  with  gutta-percha,  the  canal  is  dried  and  the  foramen 
closed. 

Willing  Root- Canals. — Of  the  man}'  materials  used  for  filling 
root-canals,  gutta-percha  is  most  approved. 

In  the  form  of  chloro-gutta-percha,  it  can  be  placed  in  the 
extreme  end  of  the  canal  with  the  aid  of  a  broach  or  fine- 
pointed  probe.  A  good  method  is  to  dip  a  few  shreds  of  iodo- 
formized  cotton1  in  the  solution,  press  out  the  surplus,  and  gently 
pack  (not  push)  them  lengthwise  into  the  extremity  of  the  canal. 
Cotton  so  prepared  is  incorruptible,  and  when  properly  inserted 
it  effectually  closes  the  foramen,  obviates  any  danger  of  air  or 
the  solution  of  gutta-percha  being  pressed  through,  and  is  easily 
removed  should  any  subsequent  condition  require  it.  The  canal 
is  then  filled  with  gutta-percha  or  any  other  material  preferred. 
If  gutta-percha  is  the  filling  used,  it  will  unite  with  the  chloro- 
gutta-percha  and  absorb  the  chloroform.  It  is  best  prepared  in 
the  form  of  "  root-canal  points."  Another  method  is  to  prepare 
an  orange  or  hickory  wood  point  to  fit  the  canal,  immerse  it  in 
the  solution  of  gutta-percha,  and  then  press  it  to  position  in  the 
canal.  Ordinary  gutta-percha  should  be  used  to  close  a  foramen 
when  an  abscess  has  just  been  treated  by  injecting  through  it. 
As  oil  of  eucalyptus  is  a  solvent  of  gutta-percha,  the  application 
of  this  oil,  alone  or  in  combination  with  iodoform  or  aristol,  is 
recommended  in  the  final  treatment  when  chloro-gutta-percha  is- 
not  used,  as  adhesion  of  the  gutta-percha  to  the  walls  of  the 
canal  is  thus  obtained. 


Cotton  or  wood  points  may  be  iodoform i zed  by  immersing  them  for  a  short 
time  in  a  saturated  solution  of  iodoform  in  ether,  and  then  exposing  them  for  a 
little  while  to  evaporate  the  ether.  The  prepared  points  should  be  kept  in  a 
tightly-corked  bottle.  When  this  plan  is  followed,  the  odor  of  iodoform  is 
almost  imperceptible  in  the  operating-room. 


TREATMENT  OF  PULPLESS  TEETH.  27 

Successful  treatment  of  pulpless  teeth  depends  not  on  "imme- 
diate root-filling  after  extirpation  of  the  pulp,"  but  upon  immediatt 
root-JUling  when  a  thorough  aseptic  condition  of  the  canals  "ml  dentim 
is  indicated  or  '/stared. 

Ample  room  should  be  left  in  any  root-canal  which  is  to 
receive  the  post  of  a  crown,  as  any  part  of  the  canal  not  occu- 
pied by  the  post  will  be  filled  by  the  retaining  material. 

A  pulpless  tooth  presented  for  crowning,  the  roots  of  which 
have  been  treated  and  filled  in  some  previous  operation,  should 
be  carefully  examined,  and  if  any  doubt  is  entertained  as  to  its 
hygienic  condition  it  should  receive  the  antiseptic  treatment 
above  described,  as  the  ultimate  success  of  crown-work  depends 
largely  upon  the  thoroughness  of  these  preliminary  operations. 


CHAP  TEE    IV. 

CHRONIC  ALVEOLAR  ABSCESS. 

Many  teeth  and  roots  presented  for  crown-work  are  affected 
with  chronic  alveolar  abscess.  A  general  description  of  an 
effective  method  of  treatment  is  therefore  properly  associated 
with  a  discussion  of  the  subject. 

The  cause  of  chronic  alveolar  abscess  will  be  found  in  a  con- 
tinuation of  those  conditions  which  originally  produced  the  acute 
form.  The  tooth  or  root  being  pulpless,  septic  gases,  generated 
by  the  decomposition  of  organic  matter  in  the  root-canal  and  in 
the  tubuli  of  the  dentine,  find  an  outlet  through  the  open  foramen 
into  the  apical  space,  causing  pericementitis  and  formation  of 
pus.  The  general  treatment  consists  in  the  removal  of  all  septic 
matter  and  gases  from  the  root-canal  and  dentinal  tubuli,  the 
destruction  of  the  pus-sac,  the  application  of  suitable  therapeutic 
agents,  and  the  adoption  of  measures  to  prevent  further  formation 
of  pus. 

Chronic  alveolar  abscess  is  usually  found  in  the  following 
forms :  1st.  Abscess  with  a  fistulous  opening  in  the  gum,  and 
accessible  through  the  root-canal  and  foramen  of  the  root.  2d. 
Abscess  with  fistulous  opening,  but  not  accessible  through  the 
apical  foramen.  3d.  Abscess  from  which  pus  discharges  through 
the  apical  foramen  and  root-canal,  with  no  opening  through  the 
gum. 

In  the  treatment  of  abscess  of  the  first  form,  the  canal  should 
be  enlarged  as  described  in  the  treatment  of  pulpless  teeth,  and 
the  foramen  opened,  if  possible,  with  a  smooth  broach  without 
the  use  of  a  drill.  Tepid  water  is  then  forced  through  the  fora- 
men with  a  fine-pointed  syringe  (Fig.  10)  introduced  wTell  up  the 
canal,  and  packed  in  with  gutta-percha,  or  it  may  be  pumped  up 
with  cotton  on  a  broach  until  it  passes  into  the  ab-cess  and  out 
28 


CHRONIC  AL  YEOLAR  ABSCESS. 


29 


Fig.  10. 


through  the  fistula.  Peroxide  of  hydrogen  is  next  used  in  the 
same  manner,  until  it  ceases  to  foam  as  it  passes  from  the  abscess. 
Aromatic  sulphuric  acid  is  then  injected  through  the  fistulous 
opening  into  the  abscess. 

In  abscesses  of  the  second  form,  where  it  is  impracticable  to 
treat  through  the  foramen,  the  canal  should  be  thoroughly  disin- 
fected, and  a  direct  opening  into  the  abscess  effected  by  the  track 
of  the  fistula,  enlarging  it  if  necessary.  The  abscess  should 
then  be  thoroughly  injected  with  peroxide  of  hydrogen,  and 
afterward  with  aromatic  sulphuric  acid,  by  introducing  the  fine 
point  of  a  syringe  into  its  deepest  parts.  The  fistula  must  be 
kept  open  by  inserting  in  it,  at  each 
injection,  a  strand  of  twisted  cotton 
saturated  with  oil  of  cloves,  the  pa- 
tient being  directed  to  remove  it  in 
a  few  hours,  or  the  next  day,  for 
which  purpose  the  end  should  be 
left  protruding.  "When  the  apical 
foramen  is  open,  one  injection  is  usu- 
ally sufficient  to  cure  an  abscess;  but 
when  the  foramen  is  closed  and  the 
abscess  is  treated  through  the  gum, 
several  injections  are  sometimes  ne- 
cessary. 

In  case  of  "blind  abscess,'"'  the 
third  form,  first  clean  and  disinfect 
the  root-canal,  then  at  intervals  inject 
the  abscess  through  the  foramen  with  peroxide  of  hydrogen 
until  the  formation  of  pus  ceases,  placing  cotton  saturated  with 
oil  of  cloves  loosely  in  the  canal  to  exclude  foreign  substances. 
Should  this  treatment  fail,  an  opening  through  the  gum  into  the 
abscess  must  be  obtained,  either  with  a  lance  and  drill  or  a  tre- 
phine, and  the  same  course  pursued  as  in  the  first  form  of  absci  ■--. 

An  entrance  into  the  apical  space  can  be  made  almost  pain- 
lessly in  the  following  manner,  as  described  by  Dr.  G.  V.  Black:1 
"The  mucous  membrane  is  first  dried  at  the  point  at  which  it  is 
desired  to  make  the  opening,  and  napkins  are  so  placed   as  to 


1  "American  System  of  Dentistry,"  vol.  i,  page  928. 


30  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

keep  it  dry.  Then  a  plugging-instrument  with  fairly  sharp 
serrations  and  of  convenient  shape  is  selected.  The  point  of 
this  is  dipped  into  a  95-per-cent.  solution  of  carbolic  acid,  and  a 
drop  conveyed  to  the  mucous  membrane ;  this  will  at  once  pro- 
duce a  white  eschar.  Then  a  slight  scratching  motion  with  the 
serrated  point  is  begun,  with  the  view  of  removing  the  tissue 
that  is  whitened.  This  is  continued  until  the  carbolic  acid  is 
thick  with  the  dtibris  of  the  tissue  torn  up,  then  it  is  dried  out 
and  another  drop  added,  as  before,  and  the  process  continued. 
This  is  repeated  as  often  as  may  be  necessary,  going  deeper  and 
deeper  into  the  tissue  in  the  desired  direction  until  the  bone  is 
laid  bare.  Then  a  fresh  drop  of  the  acid  is  placed  on  the  bone, 
and  the  periosteum  carefully  raised  over  a  sufficient  space;  then 
with  a  sharp  chisel  cut  through  to  the  peridental  membrane. 
This  will  generally  cause  some  pain  and  some  bleeding,  but 
after  giving  a  little  time  for  this  to  cease,  and  adding  more  of 
the  acid,  the  apical  space  can  usually  be  reached  without  diffi- 
culty. Xo  blood  should  be  drawn  at  any  time  during  the  opera- 
tion, except  in  penetrating  the  wall  of  the  alveolus.  In  doing  this 
no  tissue  is  removed  until  it  is  anesthetized  by  the  carbolic  acid. 
This  is  a  little  tedious,  but  it  is  almost  painless,  and  the  general 
effect  is  usually  better  than  by  other  modes  of  penetrating  the 
apical  space.  The  carbolic  acid  has  the  effect  of  modifying  the 
pain,  and  the  opening  left  does  not  close  so  readily." 

After  the  abscess  has  been  cured,  the  root-canals  are  filled  as 
described  on  page  21. 

Thorough  disinfection  and  sterilization  of  the  root-canals  are 
included  in  the  preliminary  treatment  of  alveolar  abscess.  As 
soon  as  the  treatment  is  followed  by  favorable  indications,  the 
foramen  should  be  closed,  and  the  abscess  thereafter  treated 
through  the  external  opening.  This  will  be  facilitated  by  en- 
larffinu'  the  orifice  with  tents  of  cotton  saturated  with  oil  of 
cloves.  Enlargement  of  the  fistula  tends  to  encourage  the  pro- 
cess of  granulation  in  the  region  which  has  been  occupied  by 
the  abscess. 

Aromatic  sulphuric  acid  is  a  powerful  astringent  and  germi- 
cide. It  will  be  found  most  useful  in  cases  where  a  slightly 
necrosed  state  of  the  wall  of  the  alveolus  exists.     Its  use  should, 


CHRONIC  ALVEOLAR  ABSCESS. 


31 


however,  be  limited,  and  in  subsequent  external  treatment 
through  the  fistula  some  of  the  other  therapeutic  agents  should 
be  employed,  as  the  peroxide  of  hydrogen,  sublimate  solution 
(toVo)'  or  t^e  essential  oils  or  carbolic  acid,  alone  or  combined 
with  one  of  the  preparations  of  iodine.1 

Injections  of  sulphuric  acid  in  the  region  of  the  mental  fora- 
men should  be  made  cautiously,  and  it  should  not  be  applied  to 
an  abscess  bordering  on  the  antrum  until  the  operator  is  posi- 
tively assured  that  the  abscess  does  not  open  into  that  cavity. 

Amputation  of  the  Apex  of  a  Root. — In  long-neglected  alveolar 
abscess,  the  pus-cavity  occasionally  involves  the  alveolus  in  such 
a  way  as  to  destroy  a  considerable  portion  of  the  pericementum 
of  the  end  of  the  root.  The  cementum  of  that  part  is  conse- 
quently devitalized,  and  the  portion  of  the  root  affected  becomes 
degenerated  in  structure,  and  saturated  with  septic  matter.  In 
this  condition  it  acquires  the  character  of  a  foreign  substance, 
proves  a  constant  source  of  irritation,  and  defies  all  efforts  of  the 
membranes  to  perfectly  inclose  or  encyst  it. 

In  such  cases,  amputation  of  the  portion  of  the 
root  which  is  denuded  of  pericementum  is  the 
best  course  to  pursue.  An  opening  is  made  in 
the  soft  tissues  over  the  affected  part  in  the  manner 
described  on  page  29,  and  gradually  enlarged  with 
a  tent  of  lint  or  cotton  until  the  diseased  territory 
is  fully  exposed  (Fig.  11),  when  the  devitalized  end 
of  the  root  and  any  necrosed  bone  in  the  territory 
are  removed  with  a  fissure-drill,  and  the  end  of 
the  root  smoothed.  The  root-canal  is  then  closed 
with  gutta-percha  passed  through  from  within,  the 
surplus  being  trimmed  off  on  the  outside.  Another 
way  is  to  fill  the  canal  solidly  with  gutta-percha 
previous  to  the  amputation,  so  that  when  the  end  of  the  root 
is  excised  the  stump  will  be  left  smoothly  and  snugly  filled. 
Cocaine  can  be  used  in  this  operation. 

1  For  an  extended  consideration  of  this  subject  the  reader  is  referred  to  Dr. 
J.  N.  Farrar's  articles  on  "Sulphuric  Acid  v.  Creasote  in  Treatment  of  Alveolar 
Abscess,''  commencing  in  Dental  Cosmos,  vol.  xx,  No.  7,  and  Dr.  G.  V.  Black's 
article  in  the  "American  System  of  Dentistry,"  vol.  i,  page  929. 


Fio.  II. 


32  ARTIFICIAL  CROWX-  AND  BRIDGE- WORK 

The  orifice  of  the  cavity  in  the  gum  should  be  kept  open  until 
the  cavity  is  filled  by  granulation.  AVhen  the  healing  process  is 
completed,  crown-work  can  be  proceeded  with. 

The  amputation  of  roots  requires  skill  and  experience,  and 
had  better  be  confined  to  the  incisors. 


CHAPTER  V 


SHAPING  TEETH  AND  ROOTS  FOR  CROWN-WORK. 


The  principles  governing  the  process  of  shaping  the  surface  of 
a  natural  crown  or  root  for  any  style  of  artificial  crown  with  a 
collar  attachment  require  that  the  cervical  portion  of  the  natural 
crown  and  root  shall  be  given  a  form  that  has  longitudinally 
parallel  sides  gauged  to  the  line  of  the  periphery  of  that  part. 
and  that  any  of  the  coronal  section  present  below  it  shall  be  re- 
duced at  least  sufficiently  in  size  to  come  within  this  line.  Such 
a  form  is  necessary  to  admit  of  a  perfect  adaptation  of  the  collar. 

The  coronal  section  of  a  natural  crown  to  be  prepared  is 
usually  first  ground  on  the  occluding  surface  with  as  large  a 
corundum  wheel  as  the  case  will  conveniently  admit  (Fig.  12). 

Fig.  12. 


Molars  and  bicuspids  for  all-gold  crowns  shoujd  have  enough 
substance  removed  to  make  a  small  space  between  them  and  the 
antagonizing  teeth.  The  approximal  sides  of  the  cervix  should 
be  reduced  sufficiently  to  allow  a  free  space  between  the  gold 
collar  when  adjusted  and  the  cervices  of  approximal  natural 
teeth  or  artificial  crowns.  The  approximal  surfaces  are  removed 
straight  from  the  cervical  border  to  the  occluding  surface,  using" 
corundum  or  rubber  and  corundum  disks  (Fig.  13)  and  files,  and 
last  of  all,  as  injury  to  the  approximal  teeth  is  then  more  easily 
avoided,  the  labial  and  palatal  portions,  for  which  small  corun- 
dum points  (Fig.  14)  and  wheels  are  best  adapted.  The  corners 
are  then  rounded.  The  cervical  portion,  which  includes  the 
junction  of  the  dentine  and  enamel,  is  trimmed  so  that  the  sides 

4  33 


34 


ARTIFICIAL    CROWN-   AND  BRIDGE-WORK. 


as  illustrated  at  A,  Fig.  15,  are  level  and  parallel  with  the  line 
of  the  root,  and  as  deep  as  the  collar  is  to  be  placed  (Fig.  16). 
For  this  work,  small  corundum  points,  trimmers,  and  files  can 
he  used.     Fig.  17  illustrates  a  drill,  which  in  the  ordinary  hand- 


Fig    13. 


Fig.  14. 


•  I      II       LI       111 


piece  or  in  the  right-angle  attachment  will  easily  and  quickly 
accomplish  this.  Fig.  18  illustrates  another  style,  in  the  form  of 
a  triangular  pyramid,  which  can  he  used  as  a  scraper  in  a  hand- 
socket,  bracing  the  hand  by  resting  the  thumb  on  the  adjoining 
teeth.  The  points  should  be  tempered  very  hard.  Files  shaped 
as  shown  in  Fig.  19  are  useful  in  rounding  angular  portions.  A 
smooth  surface  should  be  given  the  cervix.    On  approximal  sides 


Fig  15       Fig.  16.    Fig.  17.  Fig  18.     Fig.  19. 


Fig  20. 


AlJ 


j 


and  the  curves  to  the  other  sides,  medium  coarse  corundum  tape 
and  wheels  can  be  used  for  this  purpose. 

A  root-trimmer  or  reducer  devised  by  Dr.  W.  Storer  How 
can  be  used  in  combination  with  or  in  place  of  the  appliances 
before  described.  It  is  set  in  a  cone-socket  handle.  The  pin  of 
the  center  shaft  is  inserted  in  the  opening  in  the  end  of  the  root, 


SHAPING  TEETH  AND  ROOTS  FOR  CROWN-WORK. 


35 


and  the  scraper  point  rotated  around  the  periphery  underneath 
the  gum  margin  (Fig.  20).  The  inward  spring  of  the  flat  scraper 
shank  causes  the  point  to  bear  hard  against  the  root,  while 
following  its  outline  closely.  The  root  end  is  reduced  without 
change  of  contour,  while  its  taper  is  reversed,  so  that  the  greatest 
diameter  is  found  at  the  portion  acted  on  by  the  extreme  end 
of  the  scraper  point  (A,  Fig.  20).  The  milled  nuts  permit  the 
scraper  to  be  adjusted  to  different-sized  roots. 

In  pulpless  teeth,  the  use  of  excising  forceps  should  be  avoided 
unless  the  parts  admit  of  it  without  serious  shock  to  the  root. 
The  best  plan  is  to  make  a  succession  of  holes  with  a  spear- 
shaped  drill  across  the  portion  to  be  removed,  and  then  cut 
between  the  holes  with  a  fissure-bur  or  corundum  disk,  which 
will  permit  of  easy  removal  of  the  part  (Fig.  21). 


Fig.  21. 


Fig  22.       Fig.  23. 


Fig.  24. 


Fig.  25. 


Fig.  26. 


In  preparing  incisors  and  cuspids  for  gold  collar  crowns  with 
porcelain  fronts,  where  the  pulp  is  to  be  preserved,  the  labial 
surface  and  incisive  edge  should  be  ground  down  as  much  as 
possible  without  exposing  the  pulp  or  subjecting  it  to  irritation  ; 
the  palatal  portion  at  an  angle  from  the  cervical  border  to  the 
incisive  edge,  enough  to  level  its  prominences  of  contour  and 
form  a  slight  space  between  it  and  the  antagonizing  teeth  (Fig.  22). 
Pulpless  incisors  and  cuspids  should  be  prepared  by  grinding  the 
labial  face  to  the  gum  margin,  with  the  palatal  portion  slightly 
projecting  and  squared  off  to  the  inner  line  of  the  root-canal  (see 
Fig.  23).  Bicuspids  which  are  to  have  porcelain  fronts  are  given 
the  same  general  form  (Fig.  24). 

Bicuspids  and  molars  with  or  without  pulps,  for  all-gold  crowns. 


36  ARTIFICIAL  CROWN-  AND  BRIDGE-UORK. 

should  have  as  much  of  the  natural  crown  left  as  possible,  as  it 
affords  a  more  secure  and  more  convenient  attachment  for  the 
artificial  crown  than  any  other  method  (Figs.  25  and  26). 

It  should  be  borne  in  mind,  however,  that  unnecessarily  cut- 
ting away  the  enamel  and  dentine  of  teeth  with  living  pulps 
leaves  them  in  an  extremely  sensitive  condition,  and  is  likely  to 
result  subsequently  in  some  serious  lesion  of  the  pulp.  Slight 
sensitiveness,  such  as  may  be  readily  caused  in  proper  shaping, 
is  relieved  by  drying  the  exposed  dentine  with  hot  air  and  apply- 
ing creasote  or  carbolic  acid  two  or  three  times  as  required. 

For  the  porcelain  system,  roots  are  usually  ground  level  with 
the  margin  of  the  gum.  The  palatal  portion  in  some  cases  is  left 
a  trifle  above  the  margin.  The  root-canal  is  shaped  to  the  form 
of  the  post  or  pin  to  fit  it  tightly  (see  the  articles  on  the  Bonwill 
and  Logan  crowns).  The  occluding  edges  or  surfaces  of  antago- 
nizing teeth  should  be  removed  sufficiently  to  allow  ample  space 
for  the  artificial  crowns  or  to  favor  them  in  occlusion.  This  is 
especially  necessary  where  the  occluding  tooth,  in  the  absence 
of  an  antagonist,  protrudes  beyond  the  proper  line  of  occlusion. 
When  the  approximal  teeth  crowd  against  and  overhang  the 
cervix  of  a  root,  so  that  the  space  for  the  artificial  crown  at  the 
occluding  surface  is  less  than  at  the  prepared  cervix, — measured 
from  mesial  to  distal  side, — they  should  be  pressed  away  or  a 
small  portion  of  their  interfering  surfaces  removed.  Corun- 
dum or  composition  wheels  or  points  should  be  kept  wet  and 
cool  during  all  such  operations  in  the  mouth.  A  piece  of 
sponge,  held  against  the  wheel  with  clamping  pliers,  answers 
the  purpose  admirably,  and  also  protects  the  tongue  and  cheek 
from  injury. 

Special  Preparation  of  Badly  Decayed  Teeth  or  Boots. — The  tem- 
porary exposure  of  the  end  of  a  root  or  of  the  cervical  portion  of 
a  crowm  for  the  purpose  of  facilitating  or  simplifying  a  crowning 
operation,  especially  in  the  adaptation  of  a  collar  or  band,  is 
effected  by  inserting  in  the  pulp-chamber  or  the  root-canal  a 
piece  of  gutta-percha  large  enough  to  admit  of  a  portion  being 
brought  over  against  the  investing  membranes,  to  compress  them 
for  a  day  or  more.  TVhen  necessary  to  secure  attachment  for  the 
gutta-percha,  a  plug  of  wood  should  be  inserted  temporarily  in 


SHAPING    TEETH  AND  ROOTS  FOR  CROWN- WORK. 


37 


Fio    27. 


the  root,  and  the  gutta-percha  packed  around  it.  Roots  can  thus 
be  exposed  to  the  border  of  the  alveolar  process  if  desired.  In 
bicuspids  and  molars,  when  decay  extends  up  on  the  cervix  far- 
ther than  will  the  edge  of  the  artificial  crown  or 
the  collar,  the  gums  should  be  pressed  up  as  de- 
scribed, the  decay  removed,  retaining-pits  made, 
and  the  cavity  filled  with  amalgam  shaped  to  the 
contour  of  the  tooth  (Fig.  27).  In  incisors  and 
cuspids,  when  decay  has  destroyed  a  portion  of 
the  side  of  the  root,  a  tight-fitting  tube  of  a  metal 
to  which  amalgam  will  readilv  adhere,  and  of  such 
size  as  to  admit  the  pin  of  the  crown,  can  be  inserted  up  the 
root-canal  and  the  upper  end  cemented  in  with  oxyphosphate 
and  the  lower  with  the  amalgam  forming  the  filling  on  the  side 
of  the  root.  In  such  a  case,  the  pin  should  be  tapered  at  the 
end,  and  inserted  in  the  canal  as  deeply  as  possible  beyond  the 


Fig.  28. 


Ul 


Fig.  29. 


Fig.  30. 


m 


Fig.  31. 


end  of  the  tube,  to  gain  additional  strength  by  distributing  the 
leverage  along  the  whole  line  of  the  root. 

In  setting  a  gold  cap-crown  on  a  badly  broken-down  tooth  or 
root,  a  post  of  silver  or  iridio-platinum  wire  should  be  fitted  to 
the  root-canals  (Figs.  28,  29,  30,  and  31).  The  end  can  be  bent 
or  a  piece  of  silver  soldered  to  it.  The  post  should  then  be 
barbed  and  the  point  first  fastened  in  the  root  with  a  little  oxy- 
phosphate or  oxychloride  of  zinc,  and  the  crown  built  down 
about  two-thirds  its  length  with  a  quick-setting  amalgam,  to  be 
shaped  when  hard  and  then  roughened  to  furnish  a  better  attach- 
ment for  the  cement  with  which  the  crown  is  set.  Screws  may 
be  used  as  posts  to  support  the  amalgam.  As  the  artificial  crown 
completely  covers  the  amalgam,  the  existing  prejudice  against  its 
use  cannot  apply  to  this  method. 


PAET  II. 


ARTIFICIAL  CROWN-WORK. 


ARTIFICIAL  CROWN- WORK. 

Artificial  crown-work  aft'ords  extensive  facilities  for  restoring 
the  crowns  of  natural  teeth,  and  furnishes  means  of  support  for 
bridge-work. 

Two  general  systems  are  presented, — the  porcelain  and  the 
gold.  The  porcelain  system  includes  porcelain  crowns  with 
metallic  attachments,  with  or  without  collars,  and  the  gold 
system  gold  crowns  with  porcelain  fronts. 


41 


THE  PORCELAIN  SYSTEM. 


CHAPTER  I. 

PORCELAIN  CROWNS. 

Porcelain  crown-work  is  practiced  by  many  dentists  almost 
exclusively,  excepting  only  the  occasional  insertion  of  a  gold 
cap-crown  on  a  posterior  tooth.  The  reasons  for  this  are,  the 
intricate  character  of  the  construction  of  gold  crowns,  and  the 
objection  to  crowns  with  bands  or  collars. 

The  advocates  of  the  porcelain  system  claim  for  it  natural 
appearance,  restoration  of  contour,  strength,  and  cleanliness, 
together  with  simplicity  of  construction  and  easy  adaptation  and 
attachment  to  the  root,  to  which  the  crown  is  hermetically  sealed. 

Porcelain  crowns  are  made  in  two  general  styles.  In  one  the 
crown  is  attached  to  the  root  by  a  pivot,  post,  or  screw,  one  end 
of  which  is  cemented  in  the  root  and  the  other  in  the  crown. 
Such  are  the  Bonwill,  Gates,  Foster,  How,  and  Howland  crowns. 
In  the  other  style,  one  end  of  the  pivot,  or  post,  is  baked  in  the 
porcelain  when  the  crown  is  made,  and  the  other  end  cemented 
into  the  root  when  the  crown  is  adjusted.  The  Logan,  Brown, 
and  new  Richmond  are  of  this  class. 

Special  advantages  are  claimed  for  each  of  these  several  forms 
of  crowns.  A  general  knowledge  of  the  different  methods  is 
therefore  essential  to  determine  the  adaptation  of  each  to  the 
requirements  of  a  case. 

The  preparatory  treatment  of  the  roots  respecting  the  process 
of  grinding,  trimming,  and  shaping  is  nearly  the  same  for  all 
porcelain  crowns.     Exposing  the  end  of  the  root,  by  pressing  the 

42 


THE  BON  WILL  CROWN.  43 

gum  away  from  it'with  gutta-percha  preliminary  to  the  opera- 
tion, will  greatly  assist  the  operator,  by  enabling  him  to  avoid 
accidental  laceration  of  the  adjoining  membranes,  and  the  annoy- 
ance attending  their  bleeding,  besides  permitting  him  to  care- 
fully study  the  adjustment  and  cementation  of  the  crown.  The 
obtaining  of  a  close  joint  is  much  facilitated  in  all  forms  of  por- 
celain crowns  by  passing  a  disk  of  black  marking-paper  over 
the  post  or  pin  which  is  to  retain  the  crown,  and  placing  the 
crown  in  position  on  the  root.  The  points  which  prevent  perfect 
adjustment  are  marked  on  both  root  and  crown,  either  of  which 
can  be  dressed  oft'  accordingly  as  seems  most  desirable.  Crowns 
in  which  the  post  is  cemented  will  first  be  described. 

THE    BONWILL    CROWN. 

This  crown,  being  one  of  the  first  introduced  in  improved 
porcelain  crown-work,  has  been  very  extensively  used.  The 
process  of  its  adjustment  and  insertion  is  explained  in  a  lengthy 
article  by  its  inventor  and  advocate,  Dr.  W.  G.  A.  Bonwill,  from 
which  the  following  is  presented : 

"  These  all-porcelain  crowns  have  three  distinctive  features : 
a  concave  or  countersunk  base ;  a  triangular  opening  from  the 
base  to  a  point  at  or  near  the  cutting-edge  of  the  incisors,  the 
base  presenting  to  the  labial  surface  (at  its  upper  portion  this 
groove  is  enlarged);  a  peripheral  margin  or  border  resting  per- 


Fig.  32.— Sectional  view  of  an  incisor  crown,  from  me-ial  side,  showing  the  undercut  at  the 
point  opening  od  palatal  surface,  the  conical  base,  and  the  opening  of  the  same  to  the  retain- 
ing-grooves,  with  the  exact  relations. 

Fig.  33. — Palatal  view  of  same  tooth,  a  is  the  external  opening  for  ogress  of  alloy  ami  for 
packing  around  the  pin.  The  dotted  lines  show  the  recess  or  undercuts  on  the  mesial  and  distal 
sides  and  near  the  point  for  retaining  the  crown,  and  its  relation  with  the  conical  base 

Fig.  34.— Grinding-surface  view  of  a  superior  molar  with  the  countersunk  pin-hole-  on  the 
buccal  and  palatal  sides. 

Fig.  35. — Same  view  of  an  inferior  molar  with  the  pin-holes  on  the  mesial  ami  distal  sides. 

Figs.  36  and  37. — Sectional  views  of  a  molar  and  a  bicuspid  crown,  showing  the  countersink- 
and  their  relations  with  the  conical  base. 

Fig.  38.— Sectional  view  of  an  incisor  root,  showing  the  retaining-cuts  made  by  the  wheel-bur 
shown  in  Fig.  45. 


44 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


fectly  flat  on  the  root,  the  concavity  of  the  base  on  the  palatal 
side  being  at  a  much  more  acute  angle  than  on  the  approximal 
sides.  An  anchorage  is  made  in  the  incisors  by  a  depression  or 
undercut  between  the  labial  and  palatal  surfaces,  opening  on  the 
latter.  In  the  bicuspids  and  molars  the  retaining-pits  are  nearer 
the  grinding-surface. 

"  The  concave  base  of  the  crown  prevents  the  amalgam  from 
escaping  under  the  heavy  pressure  exerted  to  force  it  into  posi- 
tion, and  in  impacting  the  amalgam  and  expressing  the  mercury. 
It  allows  of  a  dense  body  of  material  around  the  metallic  pin, 


Fig.  39. 


B!c 


Fig  40. 


Fig.  41. 


Fig.  42. 


Fig.  43 


Fig.  44.      Fig.  45. 


Fig.  39.— End  view  of  a  canal  prepared  for  the  improved  combination-metal  pin. 

Fig.  40.— End  view  of  same  canal  as  in  Fig.  3ft,  prepared  for  a  triangular  pin,  showing  how 
much  more  of  the  mesial  and  distal  surfaces  have  been  out  away  from  it  than  in  Fig.  39  for  the 
improved  pin. 

Fig.  41. — Sectional  view  of  an  incisor  crown  and  root,  with  the  improved  pin  in  its  relative 
position  to  each,1  with  the  depressions  made  by  wheel-bur. 

Fig.  42.— Sectional  view  of  a  superior  molar,  with  the  large  angular  pin  in  palatal  root  and 
two  square  pins  in  the  bud-al  roots,  one  being  shorter  and  not  passing  through  the  crown. 

Fig.  43.— Block  of  a  molar  and  bicuspid,  showing  the  countersunk  holes  for  pins  in  the  molar, 
and  the  hole  in  the  mesial  side  of  the  second  bicuspid  where  a  pin  is  alloyed  in  and  set  into  a 
decayed  cavity  in  the  distal  surface  of  the  first  bicuspid,  being  held  upon  the  molar  roots  and 
attached  to  the  bicuspid  by  the  alloy. 

Fig  44.— Side  and  end  view  of  the  largest-size  angular  combination-metal  pin  with  the 
stamped  serrations.2  The  square  pins  are  with  >ut  serrations  and  double-pointed,  made  of  the 
same  metal  and  of  equal  thickness  throughout. 

Fig.  45.— The  smallest-sized  wheel-bur  for  grooving  the  canals  for  anchoring  the  pin  and  alloy- 

1  The  sectional  views  of  the  incisor  and  molar,  giving  th«  relative  position  of 
the  pins  in  the  crowns  and  roots,  should  show  pins  of  larger  size.  The  pins  as 
furnished  should  be  filed  down  but  little.  It  is  not  absolutely  necessary  that  so 
many  serrations  should  be  made  in  the  canals  by  the  wheel-bur  for  retaining  the 
amalgam  and  pin  as  are  shown  in  the  sectional  view  of  the  root  of  an  incisor. 

While  no  serrations  are  shown  in  the  roots  of  the  molars,  it  is  understood  that  all 
the  canals  must  have  the  serrations.  The  square  pins  in  the  canals  need  no  serra- 
tions. At  the  point  where  they  occupy  the  countersink  in  the  crowns,  make  two 
or  three  very  slight  cuts  on  the  edges  with  a  sharp  file.     The  ends  can  be  left  blunt. 

2  These  pins  are  now  made  without  serrations.  When  amalgam  is  used  for 
spcu-m£  them,  they  become  amalgamated  and  firmlv  unit"d. 


THE  BON  WILL  CROWN.  45 

giving  the  equivalent  of  a  pin  the  whole  diameter  of  the  base 
of  the  crown.  It  leaves  no  joint,  the  crown  and  root  being 
continuous.  The  amalgam  is  so  thoroughly  hardened  at  once 
by  impaction  in  the  double  concave  of  crown  and  root  as  to 
make  a  very  firm  operation.  It  prevents  any  possibility  of  the 
crown's  twisting  upon  the  pin  and  root.  In  the  event  of  fracture 
of  the  crown,  the  convex  surface  of  amalgam  on  the  root  makes 
the  substitution  of  a  new  crown  an  easy  operation.  It  enables 
the  operator  to  lit  the  crown  in  much  less  time  ;  it  allows  a 
proper  position  to  be  given  to  the  pin,  with  less  danger  of  frac- 
ture therefrom  ;  it  permits  of  a  larger  quantity  of  amalgam  in 
the  crown,  and  is  capable  of  bearing  greater  strain  ;  it  makes 
the  permanent  success  of  the  operation  probable,  from  the  fart 
that  it  is  absolutely  jointless,  and  secures  immediate  solidity. 
even  while  the  amalgam  is  semi-plastic.  These  crowns  are 
capable  of  resisting  the  force  of  biting  or  mastication,  because 
they  are  supported  nearly  to  the  cutting-edge  or  grinding-sur- 
face,  the  triangular  opening  from  the  concave  base  nearly  to  the 
cutting-edge  allowing  the  pin  to  be  imbedded  in  the  labial  face 
of  the  crown  where  there  is  the  greatest  amount  of  porcelain. 

"  The  amalgam  to  be  used  as  the  medium  of  union  must  set 
quickly  and  be  very  hard.  Thus  far  I  have  found  nothing  better 
than  the  alloys  I  have  specially  prepared  for  this  line  of  work, 
and,  though  they  are  costly,  the  superior  results  obtained  by 
their  use  amply  repay  the  cost.  I  use  No.  1  generally.  If  mixed 
thick,  it  will  set  so  quickly  that  the  operator  must  Avork  rapidly 
to  prevent  its  being  wasted.  In  incisor  cases  I  use  No.  3  at  the 
gum  line  and  make  a  close  joint. 

"  In  preparing  the  canal,  use  first  a  small-sized,  spear-shaped 
drill,  carefully  following  the  natural  channel.  Then  follow  with 
a  larger  one,  taking  care  not  to  cut  through  the  root  near  the 
apex.  On  the  mesial  and  distal  sides  cut  away  but  little,  as  there 
is  where  fractures  are  most  liable  to  occur.  The  canal  can  be 
very  tapering  and  yet  hold  the  pin.  There  need  be  but  very 
little  space  around  the  pin.  By  all  means  save  all  the  walls  of 
the  root  possible.  The  smallest-sized  wheel-bur  may  be  used  to 
make  an  interrupted  female  thread  at  various  points  along  the 
canal  to  hold  the  amalgam. 


46  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

"  If  the  patient  exposes  the  gums  much  in  speaking  or  smiling, 
the  root  may  be  cut  down  with  the  bur  or  corundum-wheel 
beyond  the  free  edge  to  conceal  the  joint.  With  bicuspids  and 
molars  it  is  not  necessary  to  go  below  the  gum;  a  joint  well 
made  will  not  be  observed,  and  the  strength  of  the  root  will  be 
preserved.  If  the  root  is  decayed  below  the  gum,  after  removing 
the  softened  parts,  fill  it  with  alloy. 

"It  is  not  necessary  that  the  face  of  the  root  should  be  flat; 
it  may  be  either  concave  or  convex,  according  to  indications. 

"  It  is  advantageous  to  take  an  impression  and  '  bite '  of  the 
root,  and  make  a  model  and  articulation  in  plaster. 

"  The  crown  to  be  inserted  should  be  inspected  closely,  as  the 
retaining  undercut  in  the  incisors  and  the  depressions  in  the 
bicuspids  and  molars  may  not  be  well  defined.  If  not,  the  crowns 
are  liable  to  work  loose.  If  the  base  has  been  ground  off  in 
fitting,  the  edges  should  be  beveled  again  to  a  fine  margin  with 
a  corundum-point.  The  crown  should  be  fitted  to  the  root  in 
the  mouth,  not  to  the  plaster  cast.  The  articulation  should  be 
clear,  to  avoid  displacement.  The  pin  should  be  as  large  as  the 
previously  prepared  canal  will  admit.  The  pin  must  in  every 
case  be  fitted,  and  in  fitting  it  file  only  on  the  plain  sides.  Leave 
the  end  sharp,  to  offer  the  least  resistance  in  passing  through  the 
amalgam.  The  end  of  the  pin  to  be  passed  into  the  crown  needs 
very  little  alteration.  The  crown  being  open  on  the  palatal  sur- 
face of  the  incisors,  permits  a  blunt-pointed  pin  to  go  up  to  its 
place.  The  middle  of  the  pin  should  not  be  interfered  with  if 
it  can  be  avoided.  It  is  well  to  cut  the  pin  a  little  short  for 
incisors,  as  it  may  not  get  pushed  entirely  up  in  the  root  through 
the  amalgam.  Small  square  pins  are  used  in  the  bifurcated 
roots  of  bicuspids  and  in  the  buccal  roots  of  molars.  They  can 
be  sharpened  at  both  ends,  but  the  outer  end  will  not  require  so 
much  sharpening.  The  palatal  roots  of  molars  will  generally 
take  one  of  the  largest  thick  pins,  with  one  square  pin  In  the 
largest  and  most  accessible  buccal  root.  Each  canal  should  have 
a  pin,  if  the  canal  can  be  reached  and  properly  prepared  to  receive 
it,  even  though  the  pin  has  to  be  so  short  as  not  to  pass  through 
thu  hole  in  the  crown.  If  it  enters  the  countersunk  base  it  will 
support  the  root.     The  lower  molars  will  require  two  of  the 


THE  BON  WILL  CROWN.  47 

largest-sized  pins.  As  the  support  of  the  root  is  dependent 
upon  the  size  of  the  pin  and  the  depth  to  which  it  is  inserted, 
single-rooted  teeth  should  have  the  very  largest  thick  pin.  If 
the  root  is  thin  on  the  mesial  and  distal  sides,  the  thin,  angular 
pin  is  to  he  preferred.  Ordinarily  these  large  pins  do  not  have 
to  be  bent.  If  necessary,  it  had  better  be  done  with  a  hammer, 
and  before  the  mercury  touches  them.  The  pin  should  have 
free  movement  in  both  root  and  crown.  Should  it  be  discovered 
that  the  pin  is  too  long  after  it  has  been  packed  in  the  root,  it 
can  be  cut  off  with  sharp  forceps,  pressing  them  up  against  the 
pin  to  prevent  displacement.  The  pin  can  be  sharpened  subse- 
quently with  the  corundum-wheel. 

"  To  insure  an  amalgamation  of  the  pin  with  the  filling, 
brighten  the  surface  of  the  former  before  inserting. 

"  The  roots,  crown,  and  pins  being  in  readiness  and  arranged 
on  the  table,  so  that  no  mistake  may  occur  from  getting  the  pin 
in  the  wrong  position,  and  the  appliances  necessary  for  the  opera- 
tion being  at  hand,  the  alloy  preferred  should  be  mixed  a  little 
thinner  than  if  intended  for  a  filling,  especially  where  the  root 
has  a  long  canal.  The  shorter  the  canal,  the  thicker  the  amal- 
gam may  be  mixed.  Mix  only  enough  at  one  time  for  one  root. 
Put  enough  amalgam  in  the  canal  to  nearly  fill  it,  but  do  not 
pack  it;  force  a  steel  pin  made  for  the  purpose,  of  about  the 
same  size  as  the  pin,  to  make  way  for  the  easier  insertion  of  the 
latter.  Then  grasp  the  pin  with  suitable  forceps,  and  carefully 
but  steadily  press  it  up  to  its  destination.  If  you  cannot  suc- 
ceed in  doing  so,  remove  it,  and  again  use  the  steel  pin.  When 
in  place,  use  an  instrument  with  a  point  small  enough  to  pass 
between  the  pin  and  the  root,  and  pack  by  tamping  the  amalgam 
around  it.  A  piece  of  bibulous  paper  placed  over  the  point  of 
the  instrument  will  assist  materially  in  carrying  the  amalgam 
before  it.  Before  the  amalgam  has  become  too  hard,  replace  the 
crown  to  determine  that  the  pin  is  in  proper  position ;  if  not,  it 
can  be  crowded  to  one  side  or  the  other  with  the  tamping-tool. 
Should  the  pin  be  found  to  be  rather  long,  it  can  be  ground  oft' 
with  the  corundum-wheel,  holding  it  meanwhile  with  the  forceps. 
No  attempt  should  be  made  to  bend  the  pin  after  it  has  been 
amalgamated,  for  fear  of  breaking  it.     If  any  amalgam  has  been 


48  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

left,  and  it  is  still  plastic,  it  may  be  packed  around  the  pin  at  the 
base  of  the  root,  using  the  bibulous  paper  as  before  directed.  If 
not,  mix  again  to  complete  the  operation.  Bank  up  the  amal- 
gam on  the  root  high  enough  to  till  the  base  of  the  crown.  The 
crown  should  now  be  tried  on,  and  forced  home  with  an  adjuster 
adapted  to  the  case,  removing  the  surplus  amalgam  if  too  much, 
or  adding  if  not  enough.  Remove  and  dry  the  crown,  and  fill 
up  simply  the  undercut  cavity  near  the  cutting-edge  if  an  incisor, 
or  the  depressions  in  the  crowns  of  bicuspids  or  molars,  allowing 
a  very  little  to  extend  into  the  cervical  base,  j^ow  force  it  home 
with  the  adjuster.  It  requires  considerable  force  to  set  one  of 
these  crowms  according  to  directions, — a  force  which  cannot  be 
applied  with  a  mallet  without  danger  of  loosening  or  displacing 
the  crown.  Steady  pressure  w7ith  slight  rotation  wTill  carry  the 
crown  into  place,  if  the  amalgam  is  not  too  hard  or  there  is  not 
too  much  of  it.  I  would  advise  you  not  to  attempt  to  set  a  crown 
without  an  adjuster  or  its  equivalent.  Free  mercury  will  be 
squeezed  out  on  the  palatal  surface,  which  should  be  wiped  off. 
Xow  hold  the  crown  in  place  wTith  the  fingers,  wTiththe  bibulous 
paper  under  the  tamping-instrument,  and  consolidate  the  amal- 
gam around  the  point  of  the  pin  in  the  crown,  absorbing  any 
free  mercury  which  appears  there.  The  excess  of  alloy  at  the 
joint  must  now  be  removed,  care  being  taken  to  press  the  crown 
up  while  this  is  being  done.  The  amalgam  packed  around  the 
pin  in  the  crown  on  the  palatal  side  should  be  as  stiff  as  may  be 
to  work  readily.  It  is  well  to  leave  over  some  of  the  first  mix- 
ing for  holding  the  pin,  and  this  will  be  about  right  for  con- 
solidating about  this  point. 

"If  in  a  bicuspid  or  molar  crown  the  pin  should  come  so  far 
through  as  to  interfere  with  articulation,  it  may  be  ground  off 
with  the  corundum-wheel  while  the  crowm  is  firmly  held. 

"  The  case  can  now  be  dismissed,  with  directions  for  the  patient 
to  return  the  next  day,  in  order  to  make  sure  that  the  articula- 
tion is  correct  and  to  dress  off  the  joint  between  the  crown  and 
root,  which  may  be  done  with  a  small  round-headed  bur. 

"  There  are  some  cases  in  which  the  root  cannot  be  filled  wTith 
anything;  if  in  a  molar,  the  pulp-chamber  can  be  relied  upon  to 
hold  a  headed  pin  or  pins.     When  a  tap-hole  is  required  in  the 


THE  HOW  CROWNS  AND  METHODS. 


49 


Fig.  48. 


root  it  can  be  made  low  down  and  at  an  acute  angle,  and  the 
amalgam  packed  around  the  root-canal  above  the  tap. 

;  Should  an  artificial  crown  be  broken,  another  F      49 
can   easily   be   substituted,    by   burring   off  any 
excess  of    amalgam,  and   using   fresh    amalgam, 
mixed  thin,  to  allow  of  ready  adjustment. 

"  Two  crowns  can  be  inserted  on  the  root  of 
one  large  molar  with  the  assistance  of  the  decayed 
approximal  surface  of  an  adjacent  tooth  (see  Fig. 
43)." 


m 


THE    HOW   CROWNS   AND    METHODS. 

These  crowns  are  the  invention  of  Dr.  "W.  Storer 
How.  There  are  two  styles, — four-pin  crowns  for 
incisors,  cuspids,  and  bicuspids,  and  porcelain 
dovetail  crowns  for  bicuspids  and  molars.  Each 
form  embraces  some  novel  features.  Dr.  How's 
methods,  being  general  in  application,  are  used  in 
inserting  other  forms  of  crowns. 

The  following  are  Dr.  How's  descriptions  and 
illustrations  of  his  methods  and  crowns  : 


Fig.  46. 


Fig.  47.      Fig.  50.     Fig.  51.    Fig.  52.   Fig.  53. 


"  The  Four-Pin  Grown. — The  difficulties  and 
uncertainties  in  mounting  artificial  tooth-crowns 
on  roots,  by  either  old  or  new  methods,  led  me  to 
a  careful  study  of  the  problem,  and  resulted  in  a  nearly 
simultaneous  devising  of  several  new  forms  of  crowns  and  ap- 
pliances for,  setting  them,  as  well' as  a  perfected  method  of  per- 

5 


50 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


forming  the  operation  of  fixing  a  peculiar  screw-post  (Fig.  46)  in 
a  root,  and  also  a  novel  process  of  attaching  the  crown  to  the 
post.  At  present  I  will  describe  simply  the  four-pin  crown  (Fig. 
47)  and  the  successive  steps  to  be  taken  in  mounting  it. 

"  1.  "When  the  root  is  in  proper  condition  for  mounting, 
measure  the  depth  of  the  canal  by  means  of  the  canal-plugger 
and  its  flexible  gauge  (Fig.  48),  and  fill  the  canal  at  and  a  short 
distance  from  the  apex  of  the  root,  keeping  the  gauge  at  position 
to  show  the  full  length  of  the  canal  and  also  the  distance  to 
which  it  has  been  filled. 


Fig.  54. 


Fig.  55. 


Fig.  56. 


Fig.  57. 


Fig.  58. 


"  2.  Cut  off  the  root-crown  with  excising  forceps  and  a  round 
file,  down  to  the  gum-margin,  and  with  barrel-bur  Xo.  241  cut 
the  labial  part  of  the  root  fairly  under  the  gum  without  wound- 
ing it. 

"  3.  Set  gauge  on  a  Gates  drill  (Fig.  49)  to  one-half  the  gauged 
depth  of  the  canal,  and  drill  to  that  depth. 

"  4.  Set  the  twist-drill  in  its  chuck  (Fig.  50)  to  project  the  same 
length  as  the  Gates  drill,  and  drill  the  root  to  exactly  that  depth. 

"  5.  Enlarge  the  mouth  of  the  canal  one-sixteenth  of  an  inch 
deep  all  around  to  near  the  margin  of  the  root,  as  shown  in 
Fig.  51.  using  square-end  fissure-bur  No.  59,  and  then  with 
oval.  Xo.  94,  undercut  a  groove  lingually  and  at  the  sides. 


THE  HOW  CROWNS  AND  METHODS.  51 

"  6.  If  the  rubber-dam  ia  to  be  used  for  a  gold  or  plastic 
backing,  put  it  now  over  the  root  with  Hunter's  root-clamp, 
also  over  the  adjacent  teeth,  and  thoroughly  dry  the  canal. 

"  7.  Set  the  tap  in  its  chuck  (Fig.  52)  a  trifle  less  in  length 
than  the  drill,  oil  it,  and  carefully  tap  the  root  to  the  gauged  depth. 

"  8.  Insert  the  post  in  its  chuck  (Fig.  53)  to  the  exact  gauge 
of  the  tap,  and  turn  the  thumb-screw  down  hard  on  the  end  of 
the  post,  then  screw  the  post  into  the  root,  release  the  thumb- 
screw, unscrew  the  chuck  a  half-turn,  bend  the  post  until  the 
chuck  stands  in  center  line  with  the  adjoining  teeth,  and  unscrew 
the  chuck  from  the  post. 

"  9.  Slit  the  rubber  back  from  adjacent  teeth,  tucking  the 
flaps  out  of  the  way,  so  that  the  occlusion  may  be  tried,  the  post 
excised  and  ground  off  until  the  teeth  close  clear  of  the  post. 

"  10.  Try  the  crown  on  the  post,  and  with  disk  F  grind  the 
rib  between  the  neck-pins  until  the  crown  is  labially  flush  with 
the  root-margin,  using  the  disk  dry  and  cutting  a  little  at  a  time 
until  exactly  flush. 

"  11.  Take  the  crown  and  place  the  mandrel  (Fig.  54)  between 
the  pins  just  as  the  post  is  to  be,  and  with  the  pliers  (Fig.  55) 
bend  the  pins  carefully  over  the  mandrel,  cutting  off  the  pins  if 
too  long  to  be  pinched  in  on  the  mandrel  at  the  sides,  observing 
that  the  pin  nearest  the  cutting-edge  is  first  to  be  bent  (Fig.  56), 
and  the  opposite  pin  bent  bdon-  it  on  the  mandrel,  and  so  with 
the  others  (Fig.  57). 

"12.  Slip  the  crown  over  the  post,  try  occlusion,  and  with 
the  post-chuck  bend  the  post  until  the  crown  is  properly  aligned 
with  the  teeth,  then  with  a  stump  corundum-wheel  No.  3  grind 
the  neck  of  the  crown  to  a  close  labial  fit  with  the  root,  fitting 
only  the  portion  to  be  concealed  by  the  gum,  leaving  narrow 
gaps  at  the  sides  to  be  filled  by  the  backing  between  crown  and 
root  (Fig.  58). 

"13.  Grind  cutting-edge  for  occlusion  and  relation  to  the 
other  teeth,  and  be  sure  that  the  opposing  tooth  does  not  strike 
the  crown,  the  post,  or  the  pins. 

"  14.  Fix  the  crown  on  the  post  by  pinching  the  pins  into  the 
screw-tliivads  in  the  post  with  the  special  pliers  for  that  purpose. 

"15.  Finally,  pack  the  backing  of  gold,  or  cement,  or  amal- 


01' 


ARTIFICIAL  CROWS-  ASD  BRIDGE-WORK. 


gam,  or  Wood's  metal,1  or — for  temporary  backing  while  treating 
abscess — gutta-percha,  into  all  the  crevices  around  the  post  and 


Fig.  59. 


Fig.  60. 


Fig.  61. 


r$&j 


behind  and  under  the  pins,  and  between  the  crown  and  the 
root ;  contour  and  finish  thoroughly,  so  that  no  ledge  or  other 
imperfection  can  be  found. 

"Fig.  59  shows  in  vertical  mid-section  an  incisor  crown 
mounted  on  a  root;  the  blackened  portions  of  the  backing- 
serving  to  define  clearly  the  locking-hold  of  the  backing  on  the 
screw-post,  the  crown-pins,  and  the  root  recess. 

"  Fig.  60  shows  in  perspective  a  cuspid  crown  ready  to  be 
slipped  over  its  post,  and  also  a  cuspid  crown  ready  for  its  post 
in  the  bicuspid  root,  which  has  its  lingual  cusp  remaining ;  and 
Fig.  61  shows  these  crowns  on  their  posts  awaiting  the  com- 
pleting or  contour-backing. 


Fig.  62. 


Fig.  63. 


Fig.  64. 


';  When  it  is  desired  to  contour  the  backing  of  a  cuspid  crown 
to  form  an  inner  cusp,  or  to  adapt  a  cuspid  or  incisor  crown  for 
masticating  uses,  the  pins  may  be  twisted  together  over  the  man- 
drel, and  again  twisted  tightly  over  the  post  as  in  Fig.  62;  but 

1  Wood's  metal  suggested  by  Prof.  J.  Taft. 


THE  HOW  CROWNS  AND  METHODS. 


53 


in  some  cases  it  may  be  better  to  bend  the  neck-pins,  as  in  Fig. 
63,  instead  of  twisting  them.  In  all  cases  the  bent  pins  are  to 
be  pinched  quite  hard  over  the  mandrel  and  post,  so  that  the 
serrations  of  the  pliers  will  roughen  the  pins  to  prevent  their 
being  pulled  through  the  backing,  which  should  also  be  carefully 
condensed  around  the  pins  and  post. 

••  When  the  root  is  much  decayed,  the  bottom  of  the  cone- 
shaped  cavity  may  be  drilled  and  tapped  to  the  depth  of  a  six- 
teenth of  an  inch,  and  the  post,  thus  anchored,  may  be  further 
secured  by  cement  in  the  grooved  walls  of  the  cavity  and  around 
the  post  (Fig.  64). 

"The  screw-posts  are  made  of  crown-metal,  an  alloy  devised 
for  the  purpose  in  order  to  obtain  a  stiff  post  that  will  permit 


Fig.  Go. 


Fig.  6»: 


Fig    67. 


Fir..    fi8. 


Fig.  69. 


the  'lining  of  the  peculiar  and  extremely  accurate  thread  formed 
upon  it.  and  which  will  not  amalgamate  or  be  otherwise  affected 
by  any  backing-material  that  may  lie  used.  Of  course  platinum 
or  platinum  alloyed  with  iridium  may  be  employed  for  posts, 
but  the  crown-metal  is  in  every  way  superior. 

"  There  are  some  cases  of  a  class  which  has  hitherto  presented 
difficulties  that  may  now  be  easily  overcome  by  grinding  the 
post  flat  on  the  crown  side  after  it  has  been  set  and  bent  in  the 
root  (Fig.  65),  so  as  to  be  clear  of  the  occluding  tooth;  and  then 
the  crown-pins  may  be  bent  over  the  reduced  post,  the  crown 
fitted  and  ground  to  clear  the  opposing  tooth  (Fig.  66),  and  the 
backing  added  in  completion. 


54 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


"A  similar  case,  in  which  the  opposing  tooth  and  a  proper 
alignment  require  an  oblique  bending  of  the  pins,  is  seen  in  Fig. 
67,  while  the  reverse  arrangement  of  parts  is  shown  in  Fig.  68. 
The  crown  is  thus  seen  to  be  adapted  to  a  wide  range  of  adjust- 
ments, because  its  point  of  contact  with  the  root  is  at  the  labial 
portion  of  the  neck,  on  which  as  on  a  hinge  the  crown  may  be 
swung  out  or  in  (Fig.  69,  dotted  lines),  over  an  arc  of  at  least 
sixty  degrees,  at  any  point  of  which  it  may  be  quickly  and  firmly 
fixed.  The  labio-cervical  junction  is  made  just  under  the  gingi- 
val margin,  and  I  usually  interpose  a  thin  layer  of  cement,  amal- 
gam, or  gutta-percha,  or  a  narrow  ribbon  or  several  large  blocks 
of  soft  gold;  the  joint  always  to  be  made  carefully  smooth,  and 
hid  from  view  under  the  free  margins  of  the  gums." 

The  Porcelain  Dovetail  Tooth-Crown.  —  These  crowns  are  de- 
signed for  the  roots  of  bicuspids  and  molars  only,  and  the  process 
of  mounting  them  may  be  very  briefly  described. 


Fig.  70.  Fig.  71.  Fig.  72.  Fig.  73.         Fig.  74.  Fig.  75. 


"Fig.  70  shows  the  roots  of  an  inferior  molar  after  the  apical 
portions  have  been  filled,  the  neck  recessed,  the  canals  drilled 
and  tapped,  and  two  How  screw-posts  firmly  fixed  therein,  the 
ends  of  the  posts  having  been  pinched  toward  each  other  by 
means  of  a  pair  of  pliers,  so  that  they  will  go  through  the  cen- 
tral opening  in  the  crown  (Fig.  71).  This  opening  is  of  a  dove- 
tail form,  as  shown  in  cross-section  by  Fig.  7_,  where  the  crown 
is  seen  in  place  over  the  posts  on  the  root.  It  is  thus  made 
obvious  that  the  crown  may  be  easily  put  on  and  off"  the  root  in 
the  process  of  fitting  the  crown-neck  to  the  root-neck,  and  also 
that,  for  occlusion,  the  crown  may  be  ground  low  on  any  or  all 
sides  without  destroying  the  dovetail  function  of  the  central 
cavity.  When  the  fitting  is  completed,  and  the  crown  cut  so 
short  as  to  be  ^  of  an  inch  distant  from  the  occluding  tooth, 


THE  HOW  CROWNS  ASD  METHODS. 


00 


amalgam  is  packed  into  the  neck  recess,  around  the  posts,  and 
thinly  over  the  cervical  margin  of  the  root,  the  crown  put  in 
place,  and,  with  thumb  pressure,  firmly  seated.  Then  test  the 
occlusion,  and  complete  the  operation  by  packing  amalgam  into 
the  crown  opening,  which  will  permit  the  forcing  of  the  amalgam 
in  all  directions,  to  insure  a  firm  base  for  the  crown,  and  its 
secure  dovetail  attachment  to  the  posts,  as  shown  by  Fig.  72. 

"The  bicuspid  crown  (Figs.  73  and  74)  is  similarly  mounted, 
as  may  be  seen  in  Fig.  75,  cross-section,'  the  same  crown  and 
root  being  shown  in  contour  by  Fig.  76.  In  some  instances  this 
bicuspid  crown  may,  like  the  Foster  crown,  be  secured  by  a 
headed  screw,  as  shown  in  Fisr.  77.  The  root  having:  been 
drilled  and  tapped  and  recessed,  and  the  crown  properly  fitted 


Fig.  76. 


Fig.  77. 


Fig.  7 


Fig.  79. 


and  articulated,  the  screw  is  put  through  the  crown,  amalgam 
packed  in  the  crown-groove  and  around  the  screw,  which  is 
then  inserted  in  the  root,  and  the  crown  pressed  hard  into  its 
place.  The  screw  is  then  turned  into  the  position  shown  in 
Fig.  77,  thus  compressing  the  amalgam  or  cement  in  both  reci  - 
and  groove,  after  which  the  screw-head  may  be  covered  with 
amalgam,  cement,  or  gold,  as  desired. 

"As  a  preferable  mode,  however,  the  screw-post  may  first  be 
fixed  in  the  root,  the  crown  adjusted  over  the  post,  amalgam 
packed  on  the  root  and  around  the  post,  the  crown  seated  firmly, 
more  amalgam  packed  in  the  crown  cavity  around  the  post,  and 
then  a  nut  screwed  on  the  post,  as  shown  in  Fig.  78.  In  all  the 
sectional  cuts  cement,  amalgam,  or  gutta-percha  is  to  be  under- 
stood as  filling  the  cavities  in  the  conjoined  roots  and  crowns. 

"Fig.  79  shows  in  contour  a  dovetailed  crown  mounted  on  a 
superior  molar  root  in  the  manner  Bhown  by  Fig.  72.  It  is 
obvious  that  the  crown  of  Fig.  72  might  be  ground  quite  down 


56  ARTIFICIAL  CROWN-   AND  BRIDGE-WORK. 

to  the  post-ends,  and  yet  be  firmly  held  by  the  dovetail  sides  of 
the  central  cavity." 

THE  GATES  CROWN. 

The  Gates  crown  has  become  identified  with  the  Bon  will, 
owing  to  its  similarity  (Fig.  80).     It  is  usually  attached  to  the 

Fig.  80. 


root  by  a  metallic  screw  manufactured  for  the  purpose,  such 

as  is  illustrated  in  Fig.  81,  instead  of  the  Bonwill  pin.1     The 

„       ,,       screw  is  first  inserted  in  the  root  and  the  amalgam 
Fig    81.  ° 

§11   packed  around  it.     In  nearly  all  roots,  at  a  reasonable 

distance  up  the  canal,  a  suitable  place  for  fastening 

the  end  of  the  screw  can  be  found.     Too  much  force 

must  not  be  applied  in  its  insertion,  as  a  root  is  easily 

split.     In  bicuspid  and  molar  crowns  nuts  are  used 

on  the  screws,  which  fit  slots  in  the  grinding-surface  of 

the  porcelain.     They  are  screwed  into  the  amalgam  or  cement, 

and  covered  with  it  in  the  process  of  cementation  of  the  crown. 

When  it  is  desirable  or  necessary  to  construct  a  screw  for  a 

special  case,  it  should  be  made  of  iridio-platinum  wire  (as  this 

alloy,  being  hard,  will  well  maintain  the  edge  of  the  thread). 

Gold  is  unsuitable,  owing  to  the  action  upon  it  of  the  mercury 

in  the  amalgam,  even  though  the  amalgam  is  used  "dry." 

In  forming  a  screw  a  coarse-thread  screw-plate  should  be  used. 

The  threads  of  most  screws  are  cut  too  fine. 

1  Dr.  Gatns  originally  used  a  double-end  cone-shaped  screw.  The  How  screws 
(seepage  49)  manufactured  by  The  S.  S.  White  Dental  Manufacturing  Company 
are  applicable  to  these  crowns. 


THE  FOSTER  AND  HOWLAXD  CROWNS. 


57 


THE    FOSTER    CROWN. 

The  Foster  crown  (Fig.  82),  which  in  general  form  is  similar 
to  a  crown  introduced  by  Dr.  H.  Lawrence,  of  Philadelphia,  in 

Fig.  82.  Fig.  83. 


1849,  also  resembles  the  Bonwill,  but  has  less  concavity  at  the 
base.     The  crown  is  attached  to  the  root  by  a  headed  screw  (Fig. 

83)  or  a  screw  with  a  nut,  instead  of  the  Bonwill  pin. 
The  How  screws  and  instruments  (Fig.  84)  are  best 

adapted  for  use  with  these  crowns. 

THE    HOWLAND    CROWN. 

This  crown,   which    is    similar    in    principle  to   one 
I  originally  introduced  by  Dr.  C.  H.  Mack,  was  devised 

by  Dr.  S.  F.  Howl  and.     It  is  attached  like  the  How 

dovetail  crown,  with  screws  that  are  first  inserted  in  the 

root.     It  is  used  mostly  on 

bicuspid  and  molar  roots,  '  85' 

and    consists  of  a   hollow 

porcelain    crown,  with    a 

cavity  in  the  crown  suffi- 
ciently  large  to  admit  the 

screw  or  pins,  and,  when 

necessary,  a  small  portion 
of  the  root  (Fig.  85). 

The  method  of  setting  this  crown,  as  described  by  Dr.  How- 
land,  is  to  shorten  the  root  even  with  the  gum  with  a  stump 
tile;  tit  the  crown  to  the  root;  enlarge  the  root-canal  so  that  a 
threaded  pin  of  proper  size  will  pass  in  easily,  partially  fill  the 
canal  with  zinc  phosphate,  and  press  the  pin  to  its  place  with 
pliers.  The  crown  should  then  be  filled  with  zinc  phosphate 
and  pressed  to  its  place,  care  being  taken  to  hold  it  in  position 
until  the  cement  sets  (Fig.  86).  If  any  operator  distrusts  the 
ability  of  zinc  phosphate  to  make  a  perfect  joint,  a  small  quan- 
tity of  silver  amalgam  or  gutta-percha  can  he  used  to  advantage. 


58 


ARTIFICIAL  CRO  WX-  AND  BR  I  DOE- WORK. 


This  crown  is  strong,  and  (luring  its  test  of  several  years  none 
have  broken  so  far  as  known.  The  mode  of  fastening  is  strong, 
and  has  the  advantage  of  two  pins  when  set  on  a  bicuspid  having 
two  root-canals.  It  is  simple,  and  when  set — no  metal  being  in 
sight — it  is  a  perfect  imitation  of  the  natural  tooth  (Fig.  87). 

THE  LOGAN,  BROWN,  AND  NEW  RICHMOND  CROWNS. 

These  crowns  have  their  platinum  posts  or  pins  baked  in  the 
body  of  the  porcelain.     In  the  Logan  crown  the  base  is  made 

Fio.  88.  Fig.  89. 


Km.  no. 


Fio    91. 


concave,  to  facilitate  its  adjustment  to  the  end  of  the  root,  and 
to  give  the  cement  a  more  reliable  form.     The  base  of  the  Brown 


Fin.   93. 


crown  is  convex,  and  that  of  the  new  Richmond  V-shaped,  from 
mesial  to  distal  side. 

The  preparation  of  a  root  for  each  of  these  crowns  is.  in 
general,  similar  to  that  for  the  Bonwill  crown.     The  root-canal 


TUE  LOGAN  CROWN. 


59 


is  enlarged,  and  shaped  so  that  the  post,  if  possible,  at  least  at 
its  point,  will  fit  tightly.  Gutta-percha  or  oxyphosphato  is  used 
for  cementing  in  preference  to  amalgam. 

Fig.  98.  Fig.  99. 


Fig.  96. 


Fig.  97. 


The  Logan  Crown. — The  Logan  crown,  now  so  extensively 
used,  is  the  invention  of  Dr.  M.  L.  Logan.  The  method  of 
mounting  is  explained  in  all  its  details  in  the  following  article 
by  Dr.  W.  S.  How : 

"Fig.  88  shows  a  superior  right  central  root,  an  end  appear- 
ance of  the  same,  and  a  Logan  crown,  front  view.  Fig.  89  ex- 
hibits, at  a  right  angle  to  the  plane  of  the  first  figure,  the  same 

Fig.   104. 


Fig.  100.       Fig.  101. 


Fig.  102. 


Fig.  103. 


root,  its  end,  and  the  Logan  crown,  side  view.  In  both 
figures  the  root-canal  is  supposed  to  have  been  first  drilled 
to  a  gauged  depth  with  an  engine  twist-drill,  Xo.  104.  and 
then  enlarged  by  means  of  a  rissure-bnr.  Xo.  70,  to  the 
tapering  form  shown  ;  the  walls  being  subsequently  grooved  with 
an  oval  bur,  X<».  no.  The  enlarged  section,  Fig.  90,  shows  the 
crown  adjusted  on  the  root  by  means  of  cement  or  gutta-percha, 
which  surrounds  the  post  and  fills  all  the  spaces  in  the  root 
and  crown.     Fig.  91  shows  the  completed  crown.     Pig.  '.'_  ex- 


t>0 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


hibits  a  bifurcated  bicuspid  root,  its  end  appearance,  and  a 
Logan  crown  adjusted  to  the  root.  Fig.  93  illustrates  the  best 
manner  of  bending  the  post.  Fig.  94  shows  a  split  post,  and  its 
adaptation  to  a  bifurcated  bicuspid  root  is  seen  in  Fig.  95. 
Figs.  96  and  97  exhibit  the  mode  of  mounting:  the  Logan  crown 
on  a  superior  molar  root,  and  Figs.  98  and  99  the  same  crown 
in  its  relations  to  an  inferior  molar  root. 

"  The  preceding  figures  clearly  present  to  the  mind's  eye  of 
the  expert  dentist  the  essential  features  of  the  Logan  crown  and 
the  method  of  mounting-  it. 

"  The  details  are  as  follows:  In  every  instance  where  a  root 
is  deemed  ready  to  receive  its  filling,  it  should  first  be  measured 
through  its  canal  from  the  cervical  opening  to  the  apical  foramen, 
and  this  may  be  accurately  done  with  a  gauge  adjustable  on  a 
delicate  canal-explorer  (Fig.  100).  The  same  device  serves  to 
measure  the  distance  from  the  apex  to  which  the  canal  should 
then  be  filled  (Fig.  101).  It  also  gauges  the  depth  to  which  the 
drill  may  be  carried.  The  proper  degree  of  enlargement  from  the 
bottom  of  the  drilled  hole  will,  of  course,  depend  on  the  observed 
size  and  character  of  the  root.  Every  dentist  should  familiarize 
himself  with  generic  tooth-forms,  so  that  when  the  length  of  an 
Fig.  105.  incisor,  cuspid,  or  other  tooth-root  is 
*  *  known,  he  can  so  nearly  determine 
its  hidden  outlines  as  to  form  with 
precision  a  corresponding  enlarge- 
ment of  the  root-canal,  such  as  is 
shown  by  the  several  cuts.  For 
preparing  the  roots,  the  Ottolengui 
root-reamers  (Fig.  105)  and  facers 
(Fig.  106)  are  very  desirable  instru- 
ments. The  reamers  are  made  in 
three  sizes  to  correspond  with  the  Logan  pins. 
With  a  root-reamer  of  the  appropriate  size,  the 
root-canal  is  enlarged  to  fit  the  pin  along  its  whole  length,  and 
so  hold  the  crown  firmly  independent/)/  of  the  cement.  With  a 
root-facer  a  labial  slope  is  given  to  the  root-end,  so  that  the 
crown  neck  shall  fit  under  the  edge  of  the  gum.  Fig.  107 
shows  the  method  and  its  result,  and  the  cross-section  shows 


Fig.   106. 


THE  LOGAN  CROWN. 


61 


how  the  cement  incases  the  pin.  The  suitable  preparation  of 
the  bifurcated  roots  of  some  bicuspids  and  of  all  the  molars 
is  a  matter  involving  difficulties  of  an  unusual  character  and 
requiring  good  judgment.  The  feasibility  of  splitting  the  post 
of  a  Logan  crown  to  adapt  it  to  the  bifurcated  root  of  a  bicuspid 
is  shown  by  Figs.  94  and  95.  This  example  directs  attention  to 
the  peculiar  shape  of  the  post,  in  which  there  is  effected  such 
a  distribution  of  the  metal  that  its  greatest  strength  is  in  the 
line  of  the  greatest  stress  that  will  in  use  be  brought  to  bear 
on  the  crown,  while  the  least  metal  is  found  at  the  point  of  the 

Fig.   107. 


least  strain;  the  applied  part  of  the  post  being  in  outline  nearly 
correspondent  to  that  of  the  root  itself.  The  root-canal  is  like- 
wise conformably  enlarged  to  receive  the  largest  and  stiffest  post 
which  the  size  and  shape  of  the  root  will  permit. 

"  The  fitting  of  a  Logan  crown  to  a  root  may  be  done  with  a 
wet  stump-wheel  in  the  engine  hand-piece.  A  safe-side  crown 
corundum-wheel  (Fig.  108)  can  be  used  in  the  same  manner. 
It  also  affords  the  greatest  facility  for  the  slight  touches  required 
to  abrade  the  thin  cervical  borders  of  the  crown,  which  may  by 
this  means  be  done  without  encroachment  on  the  post. 

"  By  the  old  method  of  adapting  pivot-teeth  to  roots,  the 
close  fitting  of  the  crown  precluded  the  use  of  a  plastic  packing, 


ARTIFICIAL    CROWN-  AND  BRIDGE-WORK. 

because  its  thinness  over  the  surface  of  the  joint  made  the  pack- 
ing liable  to  break  loose  under  the  shock  and  strain  of  use. 
The  recess  in  the  Logan  crown  obviates  this  defect  by  providing 
a  receptacle  for  a  considerable  interior  body  of  cement  that  will 
be  deep  enough  to  be  self-sustaining  internally,  and  yet  allow 
the  peripheral  portions  of  the  root  and  crown  to  approach  each 
other  so  closely  that,  though  only  a  film  of  packing  remain,  it 
will  still  be  strong  enough  to  insure  the  persistent  tightness  of 
the  joint.  This  annular  boss  if  formed  of  amalgam  also  adds 
strength  in  some  cases  to  the  mount. 

••  When  enough  of  the  natural  crown  remains,  it  is  well  to 
leave  standing  some  of  the  palatal  portion,  and  cut  the  root 
under  the   gum-margin   at   only  the  labial  part,  as  shown  by 

Fig.   108.  Fig.  109. 


Fig.  102.  The  safe-side  crownwheel  is  especially  useful  in  such 
cases  (Fig.  109).  Thus  the  labial  joining  of  the  root  and  crown 
will  be  concealed,  and  the  other  parts  of  the  joint  will  be  acces- 
sible for  finishing  and  keeping  clean  (Fig.  103).  The  Logan 
crown  may  be  ground  until  a  large  part  shall  have  been  removed 
for  adaptation  to  the  occluding  tooth  or  teeth  without  seriously 
impairing  its  strength  (Fig.  104).  This  crown  also  in  such 
cases  maintains  the  translueency  which  is  one  of  its  peculiar  ex- 
cellences, owing  to  its  solid  porcelain  body,  and  the  absence  of 
a  metallic  backing  or  an  interior  largely  rilled  with  cement  or 
amalgam. 

"  The  distal  buccal  root  of  the  natural  superior  molar  is  nearly 
always  too  small  to  receive  a  post  of  any  useful  diameter,  and 
therefore  the  Logan  superior  molar  crown  has  but  two  posts, 


THE  BRO  WN  CRO  WN. 


63 


which  like  those  of  the  inferior  molar  crown  are  square,  and  thus 
may  be  easily  barbed,  as  may  also  the  ribbed  posts  of  the  crowns 
for  the  anterior  tooth-roots.  These  posts  are  large  enough  in 
all  the  Logan  crowns  to  answer  in  any  given  case,  and  can  of 
course  be  easily  reduced  to  suit  thin  or  short  roots. 

tk  Any  of  the  cements  or  amalgams  may  be  used  in  fixing  these 
crowns,  but  good  gutta-percha,  softened  at  a  low  heat  and  quickly 
wrapped  around  the  heated  crown-post,  which  is  at  once  seated 
in  the  root,  forms  the  best  mounting  medium,  and  has  the  great 
advantage  of  permitting  a  readjustment,  or,  if  need  be,  the  ready 
removal  of  the  crown  b\  grasping  it  with  a  pair  of  hot  pliers  or 
forceps,  and  holding  it  until  the  gutta-percha  is  sufficiently 
softened." 

Th(  Brown  Crown. — Fig.  110  is  a  lateral  view  of  a  porcelain 
crown,  with  an  iridio-platinum  pin  baked  in  position,  invented  by 
Dr.  E.  Parmly  Brown.  The  pin  has  great  strength  at  the  neck 
of  the  tooth,  where  the  strain  is  heaviest,  and  this  strength  is 
further  increased  by  extending  the  porcelain  up  on  to  the  pin. 


Fig.  110. 


Fig.  111. 


Fig.  112. 


Fig.  113. 


Fig.  Ill  is  a  front  view  of  the  same  crown,  showing  by  the 
dotted  lines  the  shape  of  the  pin  and  the  position  which  it  occu- 
pies in  the  crown. 

The  pin  is  flattened  laterally,  affording  a  strong  hold  in  the 
porcelain  without  bringing  the  pin  too  near  the  surface  in  thin 
teeth,  while  it  also  permits  alteration  of  the  palatal  surface  of  the 
crown  in  a  close  "  bite  "  without  risk  of  weakening  the  body. 

Fig.  112  is  a  view  of  the  bicuspid  crown,  in  which  a  pin  is 
provided  for  each  root  of  two-rooted  bicuspids. 

Fig.  113  is  a  view  of  a  bicuspid  crown  with  the  two  pins 
pressed  together,  forming  a  single  pin  of  great  strength  tor  a 
tooth  with  only  one  root. 


64 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


The  double  pin  in  the  bicuspids  prevents  the  gradual  loosen- 
ing of  the  crown  by  the  rotary  movement  of  the  jaws  in  mastica- 
tion, which,  acting  on  the  two  cusps,  exerts  such  leverage  as  to 
sometimes  turn  and  break  down  ordinary  crowns  where  only  one 
pin  is  used. 

The  roots  are  ground  concave  to  fit  the  crowns  with  corundum- 
points  or  a  Willard  countersink  bur,  and  close  joints  are  made 
well  under  the  gum,  the  pins  being  set  with  oxyphosphate 
cement.  The  canal  should  be  enlarged  enough  only  to  admit 
the  pin,  which  should  fit  snugly  throughout  its  entire  length,  the 
better  to  distribute  the  leverage  exerted  by  the  crown,  and  thus 
directly  to  increase  the  strength  of  the  attachment.  (For  process 
of  cementation,  see  article  on  "  Insertion  and  Cementation.") 

The  New  Richmond  Grown.  —  To  illustrate  and  describe  the 
method  of  mounting  this  crown,  a  superior  left  central  incisor 
root  will  serve  as  a  typical  case,  and  its  projecting  end  is  to  be 
shaped  as  seen  in  Figs.  114  and  115.     This  can  lie  rapidly  done 


Fig.  114. 


Fig.   115. 


Fig.   110. 


with  a  narrow  safe-sided  flat  or  square  file,  the  angles  of  the 
slopes  being  such  that  the  gum  on  the  labial  and  palatal  aspects 
will  not  interfere  with  nor  be  disturbed  by  this  preliminary  work, 
as  the  root-end  is  not,  in  this  operation,  to  be  cut  quite  down  to 
the  gum.  An  Ottolengui  root-reamer  No.  2  is  then  employed  to 
bore  out  the  root  to  receive  the  crown-post,  which  is  of  the  same 
size  and  shape  as  the  Logan  crown-post  for  a  central  incisor. 

The  sectional  view  (Fig.  116)  shows  the  relation  of  the  reamer 
to  the  root.  The  new  Richmond  crown  (Fig.  117)  is  then  tried 
on  the  root  (Fig.  118),  and  its  position  relative  to  the  adjacent 


THE  NEW  RICHMOND  CROWN. 


65 


and  occluding  teeth  noted.  If  the  cutting-edge  of  the  crown  is 
to  be  brought  out  for  alignment  with  its  neighbors,  the  root  can 
be  drilled  a  little  deeper,  and  the  reamer  pressed  outward  as  it 
revolves  to  cut  the  labial  wall  of  the  cavity.  The  palatal  root- 
slope  must  then  be  filed  to  make  the  V  correspond  to  the  changed 
inclination  of  the  crown. 

Thus,  by  alternate  trial  and  reaming  and  filing,  the  crown 
may  be  fitted  to  the  root  and  adjusted  in  its  relations  until  the 
post  has  a  close,  solid  bearing  against  the  labial  and  palatal  walls 
of  the  enlarged  pulp-chamber,  and  the  crown-slopes  are  separated 
from  the  root-slopes  by  the  thickness  of  a  sheet  of  heavy  writing- 
paper.  This  space  can  be  accurately  gauged,  and  the  root-slopes 
conformed  to  the  crown-slopes  by  warming  the  crown  and  put- 


Fig.   117. 


Fig.  118. 


Fig.   119. 


Fig.  120. 


ting  on  its  slopes  a  little  gutta-percha,  so  that  an  impression  of 
the  root-end  may  be  taken,  and  the  root-slopes  dressed  with  a 
file  until  the  film  of  gutta-percha  proves  to  be  of  equal  thinness 
on  both  slopes. 

To  permanently  attach  the  crown,  Dr.  Richmond  usually  takes 
a  thin,  perforated  disk  of  gutta-percha,  pushes  the  post  through 
it,  warms  the  crown,  presses  it  into  place,  and  when  cooled 
removes  it,  and  with  a  sharp  knife  trims  away  the  gutta-percha 
close  to  the  crown-neck.  lie  then  warms  the  crown,  puts  a  very 
little  oxyphosphate  cement  on  the  post,  and  presses  the  crown 
home.     Fig.  119  show-  the  completed  crown. 

The  obvious  advantages  of  the  device  are  the  readiness  with 
which  the  slopes  of  the  root-end  may  be  shaped  with  a  tile;  the 
facility  with  which  these  slopes  may  he  given  any  angle  to  set 
the  crown  out  or  in  at  the  base  or  at  the  cutting-edge,  or  to  give 
it  a  twist  on  its  axis:   the  certainty  that,  once  adjusted,  the  final 

6 


66 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


setting  will  exactly  reproduce  the  adjustment;  the  assurance 
that  in  use  the  crown  will  not  be  turned  on  its  axis, — a  most 
common  cause  of  the  loosening  of  artificial  crowns ;  the  firm- 
ness of  its  resistance  to  outward  thrust  in  the  act  of  biting. 
This  is  made  apparent  by  Fig.  120,  wherein  it  will  be  seen 
that  in  an  outward  movement  the  crown  B  would  rock  upon  A 
as  a  pivot.  The  dotted  line  D  shows  how  the  crown-slope  is 
resisted  by  the  root-slope,  which  extends  so  far  toward  the 
incisive  edge  that  a  much  firmer  support  is  given  to  the  crown 
than  if  the  resistance  should  be,  as  it  usually  is,  on  the  line  of 
the  gingival  margin  C. 

For  roots  that  have  become  wasted  below  the  gum-surface  it 
is  not  suitable,  except  in  such  cases  as  are  decayed  under  the 
labial  or  palatal  gum-margin  only,  but  have  yet  projecting  the 
approximal  portions  of  the  crown  (Fig.  121). 


Fig.  121. 


Fig.  122. 


Fig.  123. 


The  sectional  view  (Fig.  122)  and  the  perspective  plan  views 
(Fig.  123)  illustrate  the  manner  of  mounting  these  crowns  on 
this  class  of  roots.     The  finished  crown  appears  as  in  Fig.  123. 

The  cases  for  which  this  crown  seems  specially  adapted  are 
such  as  have  some  considerable  portion  of  the  natural  crown 
remaining. 

REMARKS  ON  THE  USE  OF  PORCELAIN  CROWNS. 

Porcelain  crowns  have  some  decided  advantages.  They  are 
especially  useful  in  many  cases  where  an  inexpensive  or  easily 
adjusted  crown  is  required;  or  where  some  pathological  con- 
dition limits  the  probable  durability,  or  permanency,  of  any 
operation.  In  the  insertion  of  porcelain  crowns,  the  removal  of 
the  whole  or  a  part  of  the  natural  crown,  which  could  be  util- 
ized to  some  extent  as  a  foundation  by  other  systems,  has  given 


REMARKS  ON  THE  USE  OF  PORCELAIN  CROWNS.  QJ 

rise  to  various  objections.  If  the  natural  crown  is  entirely  cut 
away,  the  pin,  or  post,  upon  which  almost  the  entire  support  of 
the  artificial  crown  is  thrown,  acts  like  a  lever  in  the  root-canal, 
there  being  no  band  or  brace  to  relieve  the  strain.  "With  the 
whole  force  of  mastication  bearing  directly  upon  these  pulpiest 
roots,  whose  disintegration  is  slowly  but  constantly  progressing, 
the  inevitable  result  can  well  be  conjectured.  Sooner  or  later 
they  are  fractured,  and  their  usefulness  as  a  foundation  ended. 
Then,  again,  if  porcelain  crowns  are  attached  with  amalgam, 
the  discoloration  of  the  line  of  union  with  the  root,  if  subse- 
quently exposed,  is  disfiguring.  These  tacts,  and  the  lack  of 
strength  incident  to  some  forms  of  construction,  are  the  princi- 
pal objections  urged  against  porcelain  crowns  as  ordinarily 
inserted. 


CHAPTER    II. 


PORCELAIN  CROWN  WITH  GOLD  COLLAR  ATTACHMENT. 


A  gold  collar,  either  seamless  or  soldered,  can  be  used  advan- 
tageously in  combination  with  many  of  the  porcelain  crowns. 

The  root  having  been  properly  prepared,  a  collar  is  adjusted 
and  adapted  to  it  the  same  as  for  a  gold  collar  crown  (see  page 
79).     The  porcelain  crown,  the  base  of  which  should  be  fully 
as  large  as  the  end  of  the  root,  is  then  ground  even  with  the 
cervical  walls,  and  fitted  into  the  collar,  which  should  be  trimmed 
and  burnished  to  the  form  of  the  crown.     Dr.  Townsend's  fusi- 
ble metal  die,  used  in  the  following  manner,  facilitates  the  appli- 
cation of  a  collar  to  a  Logan  crown  (Fig.  124).     Enlarge  the 
Fig.  124.        root-canal    to   receive  the  Logan  pin.     Grind  a 
Logan  crown  to  fit,  and  articulate  it.     Construct 
a  band  of  No.  30  gold  (or  of  No.  32  crown-metal, 
which  is  better)  wide  enough  to  project  beyond 

an  inch.     Cut  a 

wooden  peg  about  an  inch  long 

and  taper  one  end  of  it  to  the 

general  size  and  shape  of  the 

pin  in  the  Logan  crown.    Place 

the  band  on  the  root,  insert  the 

.  socket.  ^Fusible  Metal.  peg  in  the  canal,  and  fill  up  the 

band  with  Melotte's  moldine  or 

with  stiff  putty,  pressing  it  closely  about  the  peg. 

Remove  all  together  and,  holding  the  die  over  the 

flame  of  an  alcohol  lamp  to  melt  the  fusible  metal, 

place  them — the  band,  peg,  and  moldine,  in  the 

same  relative  positions  they  occupied  in  the  root 

— on  the  die,  with  the  pin  in  the  socket,  and  press  down  until 

the  moldine  rests  on  the  surface  of  the  molten  fusible  metal. 

68 


the  end  of  the  root  say  -£%  °f 


PORCELAIN  CROWN    WITH  GOLD  COLLAR  ATTACHMENT.     69 

Chill;  in  cooling,  the  fusible  metal  takes  a  firm  hold  on  the 
lower  edge  of  the  gold  band,  holding  it  securely  in  place  during 
the   remainder  of  the    operation.      Remove  the   peg  and  the 


Fig.  125. 


Fig.  126. 


Fig.  127. 


moldine,  and  with  a  wooden  mallet  drive  the  Logan  crown  into 
the  band  until  the  porcelain  rests  upon  the  fusible  metal.  Burnish 
the  band  smoothly  about  the  crown.  AVhen  the  gold  is  perfectly 
adjusted  to  the  porcelain,  melt  the  fusible  metal  to  release  the 
band  and  crown. 

If  the  work  has  been  carefully  done,  the  crown  with  its  band 
will  then  be  ready  to  be  set,  as  the  articulation  and  fit  will  not 
have  been  disturbed. 

Enough  of  the  collar  should  be  trimmed  away  at  the  labial  por- 
tion to  prevent  too  conspicuous  exposure  of  the  gold  (Fig.  125). 

This  collar  combination  is  available  in  very  difficult  eases,  as, 


Fig    128. 


Fig.  130. 


for  instance,  when  a  root  is  decayed  upon  one  side  far  beneath 
the  gum,  as  seen  in  Fig.  126. 

Such  an  operation,  when  completed,  would  appear  in  vertical 
section  like  Fig.  127,  and  a  view  in  perspective  would  resemble 


70  ARTIFICIAL  CROWN-  AND  KRIDOE-WORK. 

Fig.  1*28.  The  collar  is  also  very  useful  wherever  the  root  and 
crown  arc  not  made  Hush  and  smooth  at  every  point,  as,  if  prac- 
ticable, they  should  always  be. 

Dr.  E.  C.  Kirk,  of  Philadelphia,  uses  for  bicuspids  and  molars 
a  Foster  crown  in  combination  with  a  collar  (Fig.  129).  A  collar 
is  made,  and,  on  being  fitted  to  the  root,  is  cut  narrow  on  the 
labial  side,  and  left  wide  on  the  lingual,  so  that  it  shall  extend 
nearly  to  the  cusp  of  the  crown  when  finished  (Fig.  130).  (The 
seamless  gold  collars  are  well  suited  for  application  to  this  style 
of  crown.) 

The  crown  selected  should  have  a  somewhat  greater  circum- 
ference at  the  base  than  the  collar,  so  that  when  ground  down 
somewhat  conically  on  its  lingual  and  approximal  surfaces,  it 
can  be  tightly  adjusted  to  the  collar.  If  a  crown  smaller  than 
the  collar  is  used,  a  tight  joint  cannot  be  made.  The  screw  is 
fitted  so  that  it  shall  hold  the  crown  in  proper  relations  with  the 
root.  The  screw  and  crown  are  then  removed,  the  parts  dried, 
and  the  root-canal  filled  with  a  slow-setting  oxyphosphate  cement, 
mixed  thin.  The  crown  is  then  pressed  into  its  position,  the 
surplus  cement  flowing  through  the  opening  in  the  porcelain 
and  filling  up  any  interstices  around  or  between  the  band,  the 
root,  and  the  crown.  The  screw  is  then  driven  into  position, 
and  when  the  cement  is  set  perfectly  hard  the  head  of  the 
screw  or  the  nut  on  it  is  notched  to  form  a  retaining-pit,  and 
the  countersink  of  the  crown  filled  with  gold. 

Dr.  C.  S.  W.  Baldwin  caps  the  root  and  attaches  a  Logan 
crown  in  the  following  manner: 

First,  the  root  is  shaped,  the  outer  margin  being  beveled 
about  the  thickness  of  the  gold  used,  to  afford  regular  sides  for 
close  adaptation  of  the  caps.  Then  an  impression  is  taken  and 
a  die  made  in  the  gold  seamless  cap  method.  To  strike  up  the 
cap,  place  No.  32  gauge  gold  plate  on  a  cushion  of  lead,  holding 
the  die  firmly  on  the  gold  where  you  wish  to  produce  the  cap, 
and  strike  until  the  required  depth  is  secured  before  removing  it. 
This  drives  the  gold  and  die  into  the  lead,  forming  a  female  die 
and  a  perfect-fitting  cap  at  once,  in  less  time  than  is  occupied  in 
describing  the  process.  Trim  the  edges  to  fit  the  festoon  of 
the  gum,  and  drill  a  hole  from  the  inner  side  for  the  pin,  leav- 


PORCELAIN  CROWN  WITH  GOLD  COLLAR  ATTACHMENT.     71 

ing  the  raggedness  made  by  drilling  to  catch  in  the  cement. 
Place  the  cap  on  the  root  and  fit  the  porcelain  crown  accurately 
to  it  in  the  desired  occlusion  and  position.  A  Logan  crown 
■can,  with  little  grinding,  be  made  to  do  good  service  (Fig.  131). 
A  crown  having  the  H-shaped  pin,  bat  square  on  the  edge,  like 
some  of  the  early  patterns  of  Logan  or  Bonwill  crowns,  would 
reduce  the  time  of  setting  and  give  best  results.  Having 
polished  the  edges  of  the  cap,  the  crown  may  be  conveniently 
adjusted  as  follows:  Place  oxyphosphate  cement  in  the  counter- 
sunk portion  of  the  porcelain,  and  in  the  canal  only  enough 
cement,  of  creamy  consistence,  to  fill  it,  as  the  pressure  required 
to  force  out  the  surplus  under  the  edges  of  the  cap  destroys 


Fig.  131. 


Fig.  132. 


Fig    133. 


Fig.  134 


many  nicely  adjusted  crowns,  leaving  bulging  irritants  instead 
of  smooth  supports.  If  proper  attention  has  been  given  to 
fitting  crown  and  root,  all  will  come  nicely  to  place,  but  in  some 
cases  of  difficult  adjustment  it  may  be  necessary  to  cement  the 
crown  to  the  cap  before  fastening  the  pin  in  the  root  (Fig.  132). 

In  most  cases  the  gold  band  will  be  invisible  and  below  the 
free  margin  of  the  gum.  Cases  may  occur  where  the  anterior 
teeth  are  prominent,  and  it  will  be  necessary  to  cut  away  the 
top  of  the  cap  in  front,  allowing  the  porcelain  to  come  directly 
in  contact  with  the  root,  the  band  going  deeper  than  in  ordi- 
nary cases,  which  prevents  the  appearance  of  gold  (Fig.  133). 

Dr.  Bonwill'8  plan  is  to  cap  the  tooth  with  a  platinum  or  gold 
cap  having  a  slot,  into  which  the  pin  passes  as  it  is  slipped  on 


72 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


the  root  (Fig.  134).  The  crown  is  then  fastened  on  with  amal- 
gam in  the  usual  manner. 

Dr.  S.  S.  Stowell  suggests  the  following  method  of  applying- 
porcelain  crowns,  with  or  without  a  countersunk  base  in  which 
a  post  can  be  cemented,  forming  what  he  calls  the  "  Simplicity 
Crown": 

The  end  of  the  root  is  prepared  in  the  usual  manner  and 
slightly  countersunk.  The  porcelain  crown  (an  ordinary  pivot 
or  a  Perry-Howland  crown)  is  then  fitted  in  position,  and  the 
glazed  surface  of  the  base  and  cavity  removed  to  secure  better 

Fio.  135. 


adhesion  of  the  cement.  A  How  screw- 
post,  preferably  of  iridio-platinum,  is  in- 
serted in  the  root  in  alignment  with  the 
cavity  in  the  crown.  After  the  screw-post  is  set,  a  groove  is  cut 
on  the  end  of  the  root,  around  the  post,  with  about  a  No.  0 
engine-bur.  This  groove  is  tilled  with  copper  amalgam,  the 
crown  placed  on  the  root,  and  the  excess  of  amalgam  pressed  out. 
The  crown  is  then  removed,  tilled  with  oxyphosphate  cement, 
and  pressed  back  in  place.  The  excess  of  cement  exudes  on  all 
sides,  and  carries  with  it  any  excess  of  the  amalgam.  The  cr<  iwn 
is  held  in  position  until  the  cement  sets.  Fig.  135  shows  an 
incisor  and  a  bicuspid  made  by  this  plan,  when  ready  for  adjust- 
ment; also,  a  sectional  view  of  the  completed  incisor. 


CHAPTER    III. 


THE  WESTON  CROWN. 


Dr.  Henry  Weston's  method  of  crowning  is  described  by 
him  as  follows : 

"This  crown  represents  on  its  labial  surface  the  ordinary  plate 
tooth,  the  lingual  or  palatal  surface  being  concaved  in  such  a 
manner  as  to  afford  the  largest  amount  of  working  room  with- 
out impairing  its  strength  at  any  point.  The  pins  are  so  im- 
bedded in  the  thickest  part  of  the  crown  that  it  is  not  liable  to 
be  weakened  by  grinding.     Fig.  136  represents  the  crown. 


Fig.  186. 


Fig.  137.         Fig.  138. 


Fig.  139.         Fig.  140.        Fig.  141. 


"The  pin  is  made  of  hard  platinum  and  iridium,  and  is  spear- 
shaped  and  notched  on  both  edges  to  give  firmness  to  its  anchor- 
age. The  backing  is  of  the  same  metal  and  strongly  soldered 
to  the  pin.     Fig.  137  represents  the  pin. 

"  The  preparation  of  the  root  for  the  reception  of  the  crown 
consists  in  the  removal  of  that  part  of  the  tooth  which  is  to  be 
replaced  by  the  porcelain.     Fig.  138  shows  the  root  at  this  stage. 

"The  canal  must  be  sufficiently  enlarged  to  allow  space  for 
packing  gold  or  amalgam  securely  about  the  pin,  and  the  sides 
reamed  |  Fig.  139). 

"  The  grinding  of  the  crown  to  the  root  requires  but  little 
labor,  and  the  fitting  may  be  done  directly  on  the  natural  root,, 
or  on  a  cast  taken  after  the  root  has  been  prepared.     This  must 

73 


74  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

always  be  done  with  the  utmost  neatness  and  precision.  When 
fitting,  the  crown  can  be  held  in  position  by  a  cone  of  wax  in- 
serted in  the  root.  Next  comes  the  adjustment  of  the  pin  to  the 
root  of  the  crown.  After  punching  holes  in  the  backing  to 
receive  the  pins  of  the  porcelain  crown,  bend  the  pin  with  small 
flat-nosed  pliers,  so  that  when  in  its  proper  position  there  shall 
be  a  uniform  space  around  its  entire  surface. 

"  Secure  the  tooth  and  pin  together  with  a  cement  of  resin 
and  wax,  invest  in  plaster  and  sand,  and  solder  with  fine  gold 
solder. 

"  It  has  been  my  practice  of  late  years  when  preparing  the 
root  to  leave  just  a  line  of  enamel  around  its  entire  circumfer- 
ence, thus  securing  a  joint  clear  of  the  free  edge  of  the  gum, 
especially  when  gold  is  used.  If  gold  is  to  be  used  as  the 
attachment,  the  rubber-dam  is  indispensable.  When  amalgam 
or  cement  is  used,  the  rubber-dam  may  be  dispensed  with  by 
those  who  prefer  other  methods  of  keeping  out  moisture.  When 
gold  is  to  be  used,  the  root  having  been  previously  properly 
treated,  and  everything  in  readiness  and  the  rubber-dam  in  place, 
put  upon  the  point  of  the  pin  a  pellet  of  phosphate  or  oxychlo- 
ride  of  zinc,  the  size  of  a  No.  7  or  No.  8  excavating  bur ;  now 
press  the  pin  and  crown  carefully  to  their  exact  position  into 
and  upon  the  root,  and  with  a  delicate  but  blunt-pointed  instru- 
ment, thin  enough  to  reach  the  end  of  the  canal,  pack  the  cement 
firmly  about  the  pin.  The  object  in  using  the  cement  is  to 
secure  the  pin  in  its  place  during  the  first  introduction  of  the 
gold.  By  using  the  hot-air  syringe,  the  cement  will  harden  in 
two  minutes.  Close  the  opening  of  the  canal  about  the  pin  with 
a  rope  of  bibulous  paper,  and  attach  the  crown  to  the  root  and 
adjoining  teeth  on  either  side  with  soft  wax;  see  that  the  joints 
are  exact  in  every  particular,  as  after  the  next  step  mistakes  are 
not  easily  remedied. 

"Paint  the  joint  from  the  labial  side  with  cement  mixed  to 
the  consistence  of  cream.  Cover  the  labial  surfaces  extending 
over  the  cutting-edges  of  the  porcelain  crown  and  adjoining 
teeth  to  the  thickness  of  three-eighths  of  an  inch  with  carefully 
mixed  impression  plaster.  When  hardened,  the  plaster  may  be 
cut  from  the  cutting-edge  of  the  crown,  and  the  wax  and  the 


THE   WESTON  CROWN.  75 

paper  removed.  Now  paint  the  palatal  sides  of  the  joint  with 
the  cement  mixed  to  a  cream-like  consistence,  applied  with  flat- 
tened root-canal  pluggers.  Harden  with  hot  air,  and  the  case  is 
ready  for  the  gold. 

"  When  tilled  and  finished,  the  exposed  dentine  and  enamel 
are  all  covered  with  cohesive  gold  and  porcelain;  the  result  will 
be  a  fac-simile  of  Figs.  140  and  141. 

"  If  preferred,  the  cement  in  the  labial  joint  may  be  dispensed 
with,  and  the  space  between  the  crown  and  the  root  carefully 
filled  with  gold  after  the  removal  of  the  plaster,  covering  all  of 
the  exposed  root  and  showing  only  a  fine  line  of  gold  at  the 
margin  of  the  gum. 

"  Where  amalgam  is  used  exclusively  for  the  attachment,  the 
greatest  accuracy  should  be  observed  in  the  proper  articulation 
of  the  crown  before  introducing  or  packing  it  and  in  removing 
carefully  all  excess,  and  the  patient  should  be  cautioned  against 
biting  on  the  crown  until  the  following  day." 


CHAPTER    IV. 

PORCELAIN  CROWNS  WITH  RUBBER  OR  VULCANITE 
ATTACHMENT. 


Fig.  142. 


Fig.  142  illustrates  the  formation  of  such  a  crown.  The  root, 
when  prepared,  extends  at  the  palatal  side  a  little  below  the  line 
of  the  gum  (A)  at  the  point  B.  A  plate  tooth 
(C)  is  ground  and  fitted  to  the  root.  An  iridio- 
platinum  post  is  then  fitted  to  the  root,  flattened 
slightly  and  bent  at  D,  and  riveted  to  the  tooth. 
The  proper  alignments  of  the  tooth  and  post  to 
the  root  are  then  obtained,  and  they  are  invested 
and  the  post  soldered  and  strengthened  at  the 
point  1).  The  backing  is  then  grooved  and 
notched  slightly,  wax  applied,  the  crown  ad- 
justed to  the  root,  and  the  wax  shaped  so  as  to 
form  a  foundation  and  overlapping  edge  at  the 
palatal  portion  (E).  The  crown  is  then  re- 
moved, invested  in  a  flask,  packed  with  rubber, 
and  vulcanized.  In  trimming  and  finishing, 
the  rubber  is  allowed  to  form  a  partial  band  or 
collar  around  the  palatal  portion  of  the  rout, 
where  it  will  not  show.  It  is  then  cemented  on  to  the  root  with 
oxy  phosphate. 

The  Weston  crown  and  the  four-pin  How  crowns  have  advan- 
tages over  ordinary  plate  teeth  in  the  construction  of  this  style 
of  work. 


76 


THE  GOLD   SYSTEM. 


CHAPTER  V. 


PORCELAIN  AND  GOLD  CROWN  WITHOUT  A  COLLAR. 


The  root  of  a  cuspid  will  be  taken  as  a  typical  case  to  illustrate 
the  construction  of  this  style  of  crown. 

The  end  of  the  root  is  prepared  the  same  as  for  a  porcelain 
crown  (Fig.  143).  The  root-canal  is  then  uniformly  enlarged  a 
reasonable  distance  up,  with  a  drill  which  will  tightly  fit  the 
opening.     Into  the  canal,  gauging  its  full  diameter,  is  fitted  a 


Fig.  143. 


Fig.  144. 


Fig.  145. 


Fig.  146. 


Fig.  147. 


piece  of  iridio-platinum  wire,  tapered  oft"  to  a  point,  so  that  by 
introducing  it  far  up  the  canal  greater  strength  can  be  obtained, 
and  the  root  rendered  less  liable  to  longitudinal  fracture  from 
pressure  in  a  forward  direction.  A  piece  of  platinum  plate,  a 
trifle  larger  than  the  end  of  the  root,  of  about  No.  30  U.  S. 
standard  gauge,  with  a  hole  punched  in  its  center,  is  then  slipped 
on  the  post,  which  it  must  fit  tightly  (Fig.  144). 

When  the  post  is  adjusted  firmly  in  the  canal,  the  platinum 
plate  is  pressed  down  on  the  root,  and  burnished  into  the  orifice 

77 


78  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

of  the  canal  around  the  post.  When  the  post  is  withdrawn  from 
the  root,  the  platinum  will  adhere  to  it,  if  fitted  closely,  with- 
out the  use  of  wax.  A  particle  of  pure  gold  with  horax  is  put 
in  the  joint,  and  melted  in  the  flame  of  an  alcohol  lamp.  Barely 
enough  gold  should  he  used  to  unite  the  parts.  "When  soldered, 
the  post  and  cap  are  again  adjusted  in  the  mouth  and  the  cap 
malleted  and  burnished  to  the  form  of  the  end  of  the  root,  so 
that  its  edge  will  leave  a  mark  on  the  platinum.  The  cap,  on 
being  removed,  should  be  trimmed  to  this  mark,  and  again  bur- 
nished on  the  root  (Fig.  145).  Sometimes  around  the  palatal 
portion  of  the  root  the  platinum  maybe  slightly  burnished  over 
the  edge.  The  post  is  then  cut  off  just  above  the  platinum,  and 
a  plate  tooth  fitted,  backed,  and  cemented  with  wax  in  position 
on  the  cap.  The  whole  is  then  removed,  invested,  and  soldered 
with  gold  at  least  twenty  carats  fine,  which  should  be  melted  in 
at  the  base  of  the  post,  as  at  this  point,  when  in  use,  the  strain 
is  very  great.  The  post  is  then  barbed,  and  the  crown  is 
cemented  to  the  root  with  gutta-percha  or  oxyphosphate  cement 
(Fig.  146). 

Dr.  F.  T.  Yan  Woert,  of  Brooklyn,  1ST.  Y.,  in  constructing 
crowns  without  collars,  shapes  the  end  of  the  root,  and  adapts  the 
cap  as  shown  in  Fig.  147.  The  slant  given  to  the  palatal  side 
aids  the  root  to  resist  force  in  a  forward  direction. 

The  advantages  of  a  collar  can  in  a  great  measure  be  given 

this  form  of  crown  by  the  addition  of  a  metal  flange,  encircling 

^      ,,„  the  palatal  section   of  the  root,  as  shown  in 

Fig.  148.  r  ' 

Fig.  148.     A  piece  of  gold  or  platinum,  similar 
A       in    shape   to  that  shown  at  A,  is  formed  and 
^atm    fitted  to  the  crown,  fixed  in  position   on   the 
^^    crown  with  wax,  and  adjusted  in  the  mouth, 
removed,  invested,  and   soldered.     After   fin- 
ishing, the  metal  flange  is  burnished  against 
the  root  before  the  crown  is  cemented. 


CHAPTER    VI. 

GOLD  COLLAR  CROWNS. 

This  style  of  gold  crown  includes  those  methods  which  consist 
in  banding,  capping,  and  hermetically  inclosing  with  gold  the 
end  or  the  neck  of  a  root,  with  or  without  any  portion  of  a 
natural  crown,  for  the  purpose  of  securing  stability  to  the  arti- 
ficial crown,  preventing  fracture  of  the  root  and  decay  of  the 
parts,  thus  permanently  preserving  them.  This  method  pos- 
sesses much  practical  value  as  a  preserver  of  tooth-structure  and 
restorer  of  usefulness  to  the  teeth,  and  affords  excellent  supports 
for  bridge-work. 

Collar  crowns,  the  use  of  which  has  become  quite  general, 
have  been  described  by  many  writers  in  the  past.  Dr.  ¥m.  H. 
Dwinelle  relates  the  application  of  the  method  to  a  crown  with  a 
porcelain  front,1  and  Drs.  W.  N".  Morrison2  and  J.  B.  Beers5 
tell  of  it  in  the  construction  of  all-gold  cap  crowns.4 

Collar  crowns  of  which  the  part  that  essentially  constitutes 
the  cap  is  constructed  in  sections,  will  be  first  described. 

THE  CONSTRUCTION  AND  ADAPTATION  OF  COLLARS. 

Careful  study  of  the  different  forms  of  crowms  and  roots,  and 
of  the  anatomical  structure  and  relationship  of  the  contiguous 
parts,  is  most  essential  for  the  perfect  construction  and  adaptation 
of  collars,  bands,  or  ferrules,  as  they  are  variously  designated. 

Many  devices  and  methods  in  use  facilitate  this  operation, 
but  its  skillful  performanee  can  only  be  attained  by  study  and 
practice,  as  is  proved  by  the  easy  and  perfect  manner  in  whieh 
it  is  done  by  experts  in  crown-  and  bridge-work,  who  use  no 
appliances  but  pliers  and  shears  guided  by  an  intuitive  percep- 
tion of  the  requirements  of  each  case. 

1  American  Journal  of  Dental  Science,  April,  1855. 

2  Missouri  Dental  Journal,  May,  1869. 

3  Circular  to  dental  profession,  1873. 

4  J.  Patterson  Clark,  1836. 

79 


so 


ARTIFICIAL   CROWN-    AND    KRIDQ E-WORK. 


Fig.   149. 


Fig.  160 


The  collar  is  preferably  made  of  coin  gold,  or  of  22-  to  23-carat 
gold  plate.  Pure  gold  plate  lined  with  platinum  is  also  used, 
and  iridio-platinum  plate  in  special  cases. 

Gold  plate  of  No.  32  to  No.  34,  or  gold  and  platinum  or 
iridio-platinum  of  No.  34  or  No.  35,  U.  S.  standard  gauge, 
affords  the  requisite  strength,  together  with  easy  adaptation  to 
the  form  of  the  crown  or  root.  The  natural  crown  or  root 
having  previously  been  properly  prepared  (see  page  33),  a  strip 
of  the  metal  is  cut  of  the  length  required,  and  generally  from 
one-fourth  to  one-half  of  an  inch  in  width  (Fig.  149).  The  end 
to  form  the  underlap  is  beveled  with  a  file.  The  strip  is  then 
bent  with  suitable  pliers  (Fig.  150)  to  the  average  form  (Fig.  1-51), 
any  special  deviation  from  such  average 
being  noted  (Fig.  152),  and  to  the  size  of  the 
cervical  periphery  of  the  root  of  the  tooth 
to  be  crowned.  It  is  then  placed  on  the 
root  and  adapted  as  closely  as  possible  to 
its  form,  with  the  upper  edge  of  the  metal 
pressing  gently  under  the  free  edge  of  any 
portion  of  the  gum  it  may  meet.  It  is  then 
removed  and  cut  so  as  to  allow  the  ends 
to  lap  over  slightly.  The  adaptation  to 
the  root  is  then  continued,  during  which 
process  the  metal  should  be  heated  and 
chilled  in  water  after  each  trial,  in  order 
to  maintain  the  shape  given  to  it.  At  the 
last  adjustment  to  the  root,  the  lap-over  is 
marked  on  the  metal  with  a  sharp-pointed 
instrument.  The  joint  is  made  at  this 
mark  by  placing  there  the  least  possible 
quantity  of  solder,  or,  better,  fluxed  solder  filings,  and  holding 
the  collar  in  the  flame  of  an  alcohol  lamp  or  a  blue  gas  flame. 
The  collar  is  then  slipped  on  the  point  of  a  small  anvil,  and  the 
joint  tapped  down  and  trimmed  level. 

The  method  by  measurement  is  as  follows :  The  root  is 
encircled  with  a  strip  of  thin  sheet  copper,  previously  annealed, 
one-sixteenth  of  an  inch  or  less  in  width,  and  the  copper  fitted 
to  the  cervix.     It  is  removed,  and  cut  so  there  will  be  a  slight 


r^v 


THE  CONSTRUCTION  AND  ADAPTATION  OF  COLLARS.  81 

lap-over  of  the  ends  on  the  root,  then  again  fitted  to  the  root, 
and  the  position  of  the  lap-over  end  marked  on  the  copper.  This 
little  strip  of  copper,  being  soft  and  flexible,  can  be  most  accu- 
rately  fitted   to   the   root 

without  inconvenience   to  Fig.  )51. 

the  patient,  and  when  re- 
moved shows  the  exact 
length  to  cut  the  gold  or 
platinum  for  the  collar. 

Upon  a  strip  of  the  metal  V^_) 

to  form  the    collar,  from        ^""^  Y^~^) 

one-quarter  to  one-half 
inch  in  width,  is  laid  the 
cupper  pattern,  and  the 
exact  length  required  for 
the  collar  is  marked  on 
the  metal,  which  is  then 
cut  a  trifle  longer  than  the 
mark  indicates  (less  than 
one-sixteenth  of  an  inch), 
to  allow  for  the  under-lap. 
It  is  then  bent  and  the  ends 
brought  together,  the  outer 
end  placed  even  or  flush 
with  the  mark,  and  sol- 
dered as  above  described. 
The  collar  is  next  bent  to 
the  shape  of  the  root,  when 
it  is  ready  to  be  adjusted. 

This  method  is  simple 
and  practical,  and  also  eco-     The  ?^  f e  of  *°  superi?r  TlT'  !n  Ty 

y  cases,  is  of  the  large  oval  form  indicated  by  the  outer 

DOmical,  as  it  accurately  line  to  the  form  of  the  first  molar.  The  small  spurs 
J~.G„~„  4.1,~  „™~        j-     c    l    j.       indicate  the  points  generally  found  the  most  suitable 

defines  the  amount  of  plate   t0  make  the  joim. 
required. 

When  a  mandrel  is  used  in  forming  a  collar,  the  size  or 
shape  is  first  taken  by  encircling  the  root  with  a  piece  of  fine 
iron  or  copper  wire,  about  Xo.  28  U.  S.  standard  gauge,  and 
twisting  the  ends  together  on  the  labial  side.     The  wire  is  then 


82 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


pressed  up  on  the  root  about  as  far  as  the  upper  edge  of  the 
collar  is  to  go,  and  burnished  to  the  sides  (Figs.  153  and  154). 
The  wire  ring  is  then  carefully  removed,  laid  on  a  piece  of  air- 
chamber  tin,  a  piece  of  flat  iron  put  over  it,  and  with  a  blow  from 
a  hammer  on  the  iron  the  wire  is  driven  into  the  tin  (Fig.  155). 
The  wire  ring  is  removed  from  the  tin,  slipped  on  a  mandrel ' 
that  represents  the  form  of  the  root  to  be  crowned,  and  pressed 
down  gently  as  far  as  it  will  go  without  stretching  the  wire  (A, 
Fig.  156).      The  distance  from  the  end  of  the  mandrel  to  the 


Fig.  152. 


Fig.   153. 


Fig.  154. 


Fig.   155. 


wire 
wire 


Fig.  156. 


is  then  measured  and  marked  on  a  strip  of  paper,  and  the 
removed.  The  £old  to  form  the  collar  is  then  bent  and 
shaped  on  the  mandrel,  with  the  edge  which 
is  to  form  the  cervical  portion  (B)  placed  a  little 
below  the  line  of  the  wire  (A),  as  shown  by  the 
measurement  previously  taken.  The  ends  of 
the  gold  are  beveled,  slightly  lapped,  and  the 
edge  of  the  lap-over  marked  (C).  The  collar  is 
then  removed  from  the  mandrel,  and,  the  ends 
being  held  together  with  common  tweezers, 
which  are  grasped  by  pliers,  or  better  still,  by  a 
small  hand-vise  (Fig.  157),  the  extreme  outer 
end  of  the  joint  is  united  by  an  atom  of  solder 
or  fluxed  solder  filings  with  a  blow-pipe.  The 
points  of  the  tweezers  prevent  the  solder  from 
flowing  along  the  joint,  the  cervical  portion  of 
which  is  left  open  for  the  present.  The  collar 
is  then  shaped  to  the  form  given  by  the  wire  in 
the  tin,  after  which  it  is  ready  for  adjustment  in 
the  mouth.     The  unsoldered  end  of  the  joint 

1  A  description  of  mandrels  will  be  found  in  the  chapter  on  the  "Mandrel 
System." 


THE  CONSTRUCTION  AND  ADAPTATION   OF   COLLARS. 


83 


permits  the  collar  to  be  easily  and  accurately  adapted  to  the  root, 
after  which  the  solder  can  be  flowed  across  the  collar  and  the 
joint  closed. 

When  the  collar  has  been  formed,  it  is  adjusted  on  the  root 
and  pressed  or,  by  the  aid  of  a  piece  of  wood,  one  end  of  which 
is  placed  across  the  outer  edges  of  the  collar,  tapped,  up  to  the 


Fig.  157. 


Fig 


Fig.  159. 


Fig.  160. 


margin  of  the  gum.     A  line  parallel  with  the  margin  is  marked 
with  a  sharp-pointed  instrument  on  the  collar  (A,  Figs.  158  and 

159),   which    is    then    re- 
moved,  trimmed    to   this 

mark,      readjusted,      and 

again  marked  (B),  and  the 

process  continued  until  the 

collar  fits  proportionately 

under  the  margin  of  the 

gum.    If,  on  adjusting,  the 

collar  is  found  a  trifle  too 
small,  it  is  easily  en- 
larged by  tapping  the 
gold  with  a  riveting 
hammer  on  an  anvil 
as  shown  in  Fig.  160. 
If,  on  the  contrary,  the 
collar  should  prove  to 
be  too  large  in  circum- 
ference, the  difficulty  can  be  remedied  by  slitting  the  gold  partly 
across  the  side  opposite  the  joint,  lapping  the  edges  slightly,  and 
soldering.     The  edge  is  then  burnished  to  the  periphery  of  the 


84 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


root.  For  this  purpose  a  set  of  burnishers  should  be  used  espe- 
cially formed  to  suit  the  different  positions  and  avoid  irritation 
of  the  margin  of  the  gum.    Such  a  set  is  illustrated  by  Fig.  161. 


The  application  of  local  anesthetics  such  as  cocaine,  carbolic 
acid,  or  a  mixture  of  tincture  of  aconite-root  and  chloroform, 
will  lessen  the  pain  attending  the  operation. 


CHAPTER    VII. 

GOLD  COLLAR  CROWNS  WITH  PORCELAIN  FRONTS. 
INCISORS    AND   CUSPIDS. 

This  style  of  crown  for  incisors  and  cuspids,  as  originally  made 
by  Dr.  C.  M.  Richmond,  and  with  which  his  name  has  become 
associated,  consisted  of  a  cap  for  the  root,  formed  of  a  band  of 
gold  capped  with  platinum  on  which  was  soldered  a  tooth  with 
a  slot  in  the  center  between  the  pins.  Through  this  slot  and  the 
center  of  the  cap  a  screw  passed  which  entered  into  a  cylinder 
previously  screwed  and  cemented  into  the  root-canal. 

The  form  of  gold  collar  crown  in  general  use  at  present  is,  in 
principle,  the  same  as  what  has  been  known  in  dentistry  as  a 
gold  pivot  tooth,  with  the  addition  of  a  gold  collar  for  the  root, 
and  having  the  advantage  of  oxyphosphate  for  its  cementation. 
These  improvements,  however,  enhance  its  value  as  a  crown, 
and  materially  change  the  process  of  its  construction.  In 
making  an  incisor  or  cuspid  crown  of  this  style,  the  collar, 
having  been  formed,  is  trimmed  even  with  the  surface  of  the 
end  of  the  root.  "With  the  collar  in  position  on  the  root,  a 
corundum-wheel  is  passed  over  the  labial  edge,  along  the  margin 
of  the  gum,  to  level  the  gold  with  the  root  and  render  it  invisible 
when  the  crown  is  finished.  The  side  of  the  wheel  used  should 
revolve  toward  the  root,  and  when  necessary  be  reversed  for  that 
purpose,  so  as  to  turn  the  feather-edge  of  the  metal  of  the  collar 
over  the  end  of  the  root.  The  work  will  then  present  the 
appearance  shown  in  Fig.  li>2. 

The  cap  is  made  by  adapting  the  surface  of  a  very  thin  piece 
of  platinum  plate  to  the  outer  v(\^^  of  the  collar,  and  uniting 
them  with  solder  in  the  flame  of  a  lamp  (Fig.  163).  The  quan- 
tity of  solder  used  must  he  very  small,  and  it  should  be  placed 
on  the  platinum  outside  of  the  collar,  as  otherwise  it  will  flow 
over  the  inside  of  the  collar  and  interfere  with  the  fit  of  the  cap. 

85 


86 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


The  process  is  facilitated  by  first  merely  attaching  the  platinum, 
with  the  solder,  to  the  edge  of  the  collar,  then  readapting,  and 
finishing  the  soldering.  The  platinum  is  then  trimmed  to  the 
collar,  and  the  cap  adjusted  on  the  root.  The  labial  section  of 
the  surface  of  the  cap  is  then  burnished  to  the  end  of  the  root 
(A,  Fig.  162).  The  root-canal  having  been  slightly  enlarged,  a 
pin  of  round  iridio-platinum  wire,  jSTo.  16  or  17,  U.  S.  standard 
gauge, — filed  a  little  smaller  for  laterals  or  other  roots  which 
require  it, — is  slightly  tapered  at  the  point,  fitted  to  an  aperture 
made  in  the  cap,  and  to  the  canal  (B).  The  pin  is  then  cut  off 
even  with  the  cap,  removed,  and  temporarily  laid  aside. 

A  hollow  wire,  the  open  space  in  the  center  of  which  is  very 
small,  has  been  introduced  for  use  in  crown-work  by  Dr.  J.  G. 
Morey.  The  advantage  it  confers  is  the  comparatively  easy 
manner  in  which  it  can  be  drilled  out  of  the  canal  if  for  any 


Fig.  162. 


B-JUn 


Fig.   163. 


Fig.  164.  Fig.  165. 

=3 


reason  it  becomes  necessary  to  remove  the  crown,  as  the  drill 
will  follow  the  tine  opening  in  the  center  of  the  wire. 

A  plain-plate  cross-pin  tooth,  suitable  in  form  and  color,  is 
ground  and  fitted  in  position  on  the  cap.  The  labio-cervical 
edge  of  the  porcelain  (A,  Fig.  164)  should  be  Hush  with  the  edge 
of  the  collar,  and  meet  the  margin  of  the  gum.  It  should  be 
cut  out  at  the  base  (B)  so  as  to  form  a  slight  space  just  over  the 
end  of  the  pin.  The  tooth  is  then  backed  with  very  thin  pure 
gold,  gold  lined  with  platinum,  or  pure  platinum  foil.  Platinum 
gives  a  faint  blue  shade,  and  gold,  or  gold  lined  with  platinum, 
if  the  gold  side  is  toward  the  porcelain,  a  slight  yellow  shade. 
The  backing  should  extend  as  far  as  possible  under  and  between 
the  tooth  and  the  cap,  as  the  solder  will  flow  in  and  fill  the  space, 


GOLD  COLLAR  CRO  WXS  WITH  PORCELAIN  FRONTS.  87 

thus  giving  strength  and  continuity  of  structure.  The  backing, 
if  bent  over  the  incisive  edge  (C)  at  an  obtuse  angle,  will  protect 
the  porcelain  in  occlusion.  A  narrow  strip  of  tine  gold  placed 
transversely  across  at  that  point  previous  to  investing,  and  united 
in  the  soldering  of  the  backing,  will  answer  the  same  purpose. 
If  the  platinum  backing  used  is  of  the  nature  of  foil,  it  is 
advisable  to  rivet  a  small  piece  of  gold  plate  over  it  on  the  back 
of  the  tooth,  to  insure  against  melting  the  platinum  off  the  por- 
celain with  the  gold  solder,  which  may  occur  if  a  pointed  flame 
is  used. 

The  tooth,  when  backed,  is  secured  in  position  on  the  cap 
with  a  compound  of  wax  and  resin,  and  the  whole  adjusted  in 
the   mouth,  then   removed,  and  the   pin,  which   has  been  laid 

Fig.  166.  Fig.  167.  Fig   168. 


aside,  warmed  and  placed  in  position  by  passing  the  end  from 
the  inside  of  the  cap  through  the  hole  into  the  wax  attaching 
the  porcelain  crown.  Another  adjustment  in  the  mouth  is  then 
made  to  determine  the  exact  line  for  the  pin,  and  the  case  is 
ready  for  investment. 

After  the  fitting  of  the  pin  to  the  root  and  root-canal,  as  lias 
been  described  when  the  cap  was  formed,  some  prefer  to  solder 
it  to  the  eap,  for  which  purpose  it  should  be  adjusted  in  position 
and  cemented  witli  wax.  then  removed,  invested,  and  soldered 
(Fig.  165).  At  this  stage  of  the  work,  if  desired,  an  impression 
can  betaken  in  a  small  impression  cup  (Pig.  166)  with  either 
plaster  or  modelling  composition.  The  eap  should  he  removed  in 
position  in  the  impression.  To  aid  this,  a  piece  of  gutta-percha 
can  be  put  on  the  end  of  the  pin  projecting  from  the  cap.  An 
articulation  of  the  lower  teeth  should  also  be  obtained.     AVhen 


88  •  I  HTIFICIAL  CRO  WN-  AND  BRIDGE-  WORK. 

the  model  is  made,  the  pin  is  cut  off  even  with  the  cap,  and  the 
porcelain  tooth  titted  as  already  described. 

Calcined  marble-dust  and  plaster,  in  the  proportion  of  two 
parts  of  marble-dust  to  one  of  plaster,  to  which  is  added  a  pinch 
of  sulphate  of  potassium  to  quicken  the  setting,  makes  what  is 
considered  to  be  the  most  suitable  investing-  material  for  crown- 
work.  The  crown,  when  invested,  should  be  left  exposed  at  the 
sides,  as  illustrated  in  Fig.  167.  The  investment  should  be 
first  heated  over  a  Bunsen  burner,  and  then  removed  to  a  char- 
coal soldering-bloek.  Gold  solder  cut  in  small  pieces  is  then 
placed  in  and  over  the  aperture  between  the  porcelain  front  and 
the  cap.  By  uniformly  heating  the  investment,  especially  under- 
neath, with  a  large  flame  from  a  gas  blow-pipe,  mostly  pointed 
in  the  direction  A,  the  solder  is  melted  and  flowed  between  the 
porcelain  and  cap.  More  solder  should  be  added,  and  melted  in 
this  manner  until  the  space  between  cap  and  porcelain  is  filled 
in ;  but  if  an  excess  is  used,  it  is  apt  to  bulge  or  flow  out  over 
the  collar.  Additional  solder  is  then  placed  on  the  backing  and 
cap,  and  with  a  small  pointed  flame  melted  and  flowed  over  these 
parts.  Only  sufficient  gold  should  be  used  to  insure  restoration 
of  contour.  When  soldered,  after  having  been  placed  in  acid 
and  thoroughly  -divested  of  borax,  the  crown  is  ready  for  the 
finishing  and  polishing  process.  Fig.  168  represents  the  com- 
pleted crown. 

BICUSPIDS    AND    MOLARS. 

Bicuspids  crowned  by  this  method  will  have  greater  strength 
if  a  portion  of  the  palatal  section  of  the  natural  crown  is  reserved 
(Fig.  24),  and  the  band  or  collar  made  deep  enough  to  cover  it. 

The  end  of  the  root  is  capped  after  the  manner  of  the  typical 
central  already  described,  one  or  two  pins  being  used  in  the 
canals  as  required.  A  porcelain  cuspid  tooth,  or  a  bicuspid 
front,  is  then  ground,  backed,  and  adjusted  on  the  cap  to  repre- 
sent the  labial  aspect,  and  secured  with  wax.  The  front  and 
cap  are  then  removed,  invested,  and  soldered,  after  which  they 
are  adjusted  in  the  mouth,  and  the  occluding  edge  of  the  por- 
celain is  ground  clear  of  the  antagonizing  teeth  (A,  Fig.  169). 
With  a  die  of  suitable  size  representing  the  occluding  sur- 
face of  a  bicuspid,  as  illustrated  in  Fig.  170,  a  thin  piece  of  pure 


GOLD  COLLAR  CROWNS  WITH  PORCELAIX  FRONTS. 


89 


gold  plate  is  swaged  (Fig.  171)  and  the  cusps  filled  in  with  18-  or 
20-carat  gold  plate.  The  cap  is  then  trimmed  (Fig.  172),  ground, 
and  fitted  to  the  occluding  edge  of  the  porcelain  front  (Fig.  1 
in  proper  position  as  regards  occlusion,  and  the  wax  attaching 
it  is  shaped  to  the  contour  of  the  crown  (A).  A  piece  of  pure 
gold  plate  (15).  not  over  ?A  or  35  U.  S.  standard  gauge,  is  then 


Fig.  169.       Fig.  170.  Fig.  171.  Fig.  173. 


Fig.  174. 

B 


adjusted  on  each  side  of  the  crown,  which  is  invested  (Fig.  174). 
The  long  ends  of  the  two  side-pieces  of  gold  plate  are  designed 
to  retain  them  in  position,  as  the  investing  material  should  be 
removed  from  the  portion  inclosing  the  sides  of  the  crown  i  A  i. 
Mica — isinglass — is  recommended  for  this  purpose,  and  is  prefer- 
able to  metal.  In  the  process  of  soldering,  the  solder  is  placed 
in  the  aperture  at  B,  and    the   flame  of  the  blow-pipe   being 


Fig.  175. 


Fig.  176. 


Fig.  17" 


Fig.  178. 


directed  on  the  exposed  sides  of  the  gold  at  A,  the  solder  is 
flowed  into  every  part,  forming  perfect  continuity  of  structure 
of  the  metallic  portion  of  the  crown.  If  this  aperture  at  A  i- 
left  open  without  the  gold  or  mica,  and  the  solder  is  first  flowed 
in  the  interstices  as  described  in  soldering  an  incisor  crown,  the 
remaining  solder  necessary  to  contour  the  part  can  be  added,  if 
the  pointed  flame  is  used  and  not  applied  to  the  other  portions 
of  the  crown  and  investment.     In  finishing,  the  surplus  gold  is 


<l()  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

trimmed  to  the  contour  of  a  bicuspid  tooth.  Fig.  175  represents 
the  finished  crown. 

The  method  described  produces  a  perfect  and  artistically 
formed  crown,  but  simpler  and  quicker  methods  are  practiced. 
One  of  these  is  to  build  up  the  palatal  cusp  with  several  pieces 
of  gold  plate,  which  have  been  previously  melted  into  the  form 
of  small  balls  and  flattened  out  on  an  anvil.  These,  laid  in  posi- 
tion and  united  with  solder,  are  shaped  in  finishing  to  represent 
the  palatal  cusp  (Fig.  176).  The  porcelain  front  should  be 
backed  so  that  the  solder  can  be  flowed  over  its  occluding  edge. 

Another  method  is  to  extend  the  palatal  part  of  the  collar  down 
.as  shown  in  Fig.  177,  and  then  fill  in  the  space  with  solder. 
In  finishing,  the  gold  is  trimmed  to  the  form  of  the  crown.  In 
this  and  in  the  method  just  previously  described,  the  porcelain 
front  can  be  soldered  and  the  palatal  cusp  formed  in  the  one 
investment. 

The  method  of  construction  of  molar  crowns  with  porcelain 
fronts  is  similar  to  that  for  bicuspids  (Fig.  178). 

Dr.  StowhWs  Method. — A  porcelain  crown  can  be  soldered 
on  the  cap,  according  to  Dr.  S.  S.  StowelPs  method, as  follows: l 
"  The  tooth  used  may  be  a  Logan  or  an  E.  Parmly  Brown  crown 
or  an  ordinary  countersunk  tooth,  but  in  most  cases  the  Logan 
crown  is  preferable.  The  pin  is  first  cut  oft",  then  the  tooth  is 
ground  to  fit  on  the  cap,  the  porcelain  and  the  stump  of  the  pin 

Fig.  179.  Fig.  180.  Fig.  181.  Fig.  182.  Fig.  183. 


(5 


being  reduced  alike  evenly  and  smoothly  ;  after  which  the  stump 
of  the  pin  is  ground  with  a  small  wheel  below  the  surface  of 
the  porcelain  (Fig.  179).  The  tooth  is  then  invested  (Fig.  180) 
and  pure  gold  fused  on  to  the  platinum  pin,  and  while  in  a  fluid 
state  it  is  with  a  wax  spatula  '  spatted '  down  flat  (Fig.  181). 

1  Denial  Cosmos,  vol.  xxix,  page  641. 


GOLD  COLLAR  CROWNS  WITH  PORCELAIN  FRONTS. 


91 


The  gold  is  then  filed  or  ground  down  even  with  the  porcelain, 
and  at  the  palatal  border  the  tooth  is  ground  to  bevel  back  until 
the  gold  is  reached  (Fig.  182).  The  tooth  is  then  secured  in 
place  on  the  cap  with  wax  cement  (Fig.  183),  the  case  invested, 
and  heated  until  the  wax  has  melted  and  burned  out.  A  small 
clipping  of  thin  platinum  plate  is  crowded  into  the  opening  (Fig. 
184)  caused  by  the  grinding  of  the  bevel  on  the  crown.  The 
clipping  of  platinum  serves  as  a  lead  for  the  solder,  which  fol- 
lows it  down  into  the  countersunk  cap,  around  the  ends  of  the 


Fig.  184. 


Fig.  185. 

~:Z" 


Fig.  186. 


Fig.  187. 


Fig.  188. 


dowels,  and  finally  attaches  itself  to  the  pure  gold  already  at- 
tached to  the  stump  of  the  platinum  pin.  Fig.  185  represents 
the  completed  crown.  A  sectional  view  of  a  like  crown  (Fig. 
186)  also  shows  the  organization  in  detail.  A  porcelain  crown 
can  be  used  to  represent  any  of  the  teeth  in  the  same  manner. 


See  Figs.  187  and  188." 


CHAPTEK    VIII. 

ALL-GOLD   COLLAR  CROWNS  FOR  BICUSPIDS  AND  MOLARS 
CONSTRUCTED  IN  SECTIONS. 

The  root  and  crown  having  been  properly  prepared,  the  collar 
is  formed  and  adjusted  as  described  at  page  80,  and  the  edge 
toward  the  antagonizing  teeth  trimmed,  to  fully  clear  them  in 
occlusion.  The  collar  is  then  slightly  expanded  toward  the 
occluding  surface  to  effect  contour.  A  close  knuckling  can  be 
insured  by  seizing  the  collar  and  the  approximal  tooth  in  the 
manner  shown  in  Fi£.  189.     The  crown  is  removed,  filled  with 


Fio.  189. 


Fig.  190. 


plaster,  and  adjusted  in  position.  Fig.  190  represents  a  typical 
case.  The  antagonizing  teeth,  having  been  covered  with  a  piece 
of  tin  foil,  are  then  occluded  until  the  plaster  sets.  The  collar 
is  then  removed.  The  surface  of  the  plaster  inside  the  collar 
will  give  the  impression  of  the  natural  root  or  crown,  and  the 
outside  that  of  the  antagonizing  teeth.  The  latter  furnishes  an 
outline  of  the  grinding-surface  of  the  crown. 

The  plaster  is  then  trimmed  and  shaped  to  represent  the  cusps 
and  fissures  of  the  natural  tooth,  enough  of  the  surface  being 
removed  to  allow  for  the  thickness  of  the  plate  that  forms  the 
cap.  Readjustment  in  the  mouth  will  show  the  accuracy  of 
the  occlusion. 
92 


ALL-GOLD  COLLAR  CROWNS  CONSTRUCTED  IN  SECTIONS.     93 

A  -mall  tube  of  copper,  a  trifle  larger  in  circumference  than 
the  crown  under  construction,  is  filled  with  Melotte's  "moldine," 
and   the   surface    rubbed    with 


Fig.  191. 


Fig.   192. 


soapstone.  An  impression  of 
the  lower  portion  of  the  form  of 
the  crown  A  to  the  line  B,  Fig. 
191,  is  then  made  in  the  mold- 
ine, and  a  strip  of  paper  wound 
around  the  tube,  extending 
about  an  inch  above  the  edge. 
Fusible  alloy  is  then  melted 
and  poured  into  the  mold,  thus 
forming  a  die.  An  indentation 
is  made  with  a  punch  in  a  block 
of  lead,  into  which  the  die, 
when  cold,  is  hammered  slightly  beyond  the  impression  of  the 
edge  of  the  collar.  By  this  method  a  die  and  a  counter-die 
(Fig.  192)  can,  with  practice,  be  completed  in  five  minutes. 
AVith  this  die  the  cap  is  then  struck  up  on  the  lead  from  a  flat 
piece  of  plate  and  fitted  to  the  collar.  A  little  of  the  surface  of 
the  plaster  in  the  collar  may  have  to  be  removed,  if,  on  trial  in 
the  mouth,  the  cap  is  found  a  little  flush.     The  crown,  with  the 


A,  Fusible  die. 

B,  Counter-die. 

C,  Plate  to  form 
the  cup. 


Fig.  193. 


Fig.  194 


The  frame  of  this  clamp  is  formed  of  iron  wire,  and  the 
support  for  the  crown  of  plaster,  asbestos,  and  marble-dust. 

plaster  still  inside  the  collar,  is  fixed  in  a  soldering-clamp  con- 
structed in  one  of  the  forms  shown  in  Figs.  193  and  194,  which 
holds  the  parts  together  and  permits  the  flame  to  reach  all 
points.  No  more  solder  should  be  used  than  the  contour 
requires,  as  an  excess  necessitates  additional  labor  in  finishing. 


94 


ARTIFICIAL  CROWN-   AND  BRIDGE.  WORK. 


Another  method,  if  the  crown  is  not  to  be  contoured  with  the 
aid  of  the  solder,  is,  when  the  cap  is  struck  up,  to  melt  solder 
into  the  cusps,  and  then  adjust  the  cap  in  position  on  the  collar, 
for  which  purpose  some  of  the  plaster  underneath  the  cap  must 
be  removed.  A  jet  of  flame  from  the  blow-pipe  is  then  thrown 
upon  it  in  such  a  way  as  to  cause  the  solder  to  flow  down  on  the 
edge  of  the  collar  and  fill  the  seam  from  the  inside.  The  objection 
to  this  method  is  that,  when  a  large  portion  of  the  natural  crown 
is  inclosed  by  the  gold,  the  solder  will  occasionally  alter  the 
inside  form  of  the  fitted  cap,  thereby  interfering  with  its  adjust- 
ment, which  is  a  defect  troublesome  to  correct. 

Still  another  method  is  to  adjust  the  collar  in  the  mouth,  and, 
with  a  small  piece  of  wax  or  impression-compound  pressed 
upon  it,  to  take  an  impression  and  "  bite,"  in  which  the  collar 
will  be  imbedded  and  removed.  With  this  a  model  and  articu- 
lation are  made  and  the  form  of  the  cap  shaped  in  wax.  An 
impression  of  the  cap  is  then  made,  either  in  moldine  in  a  soft 

Fig.  196. 


Fig.  195. 


Fig.  197. 


state  in  a  tube,  or  in  plaster,  and  a  die  cast.  The  cap  is  stamped 
on  this  die,  then  adapted  to  the  collar  by  the  model,  and  the 
crown  finished.  This  method,  which  was  first  made  known  by 
Dr.  1ST.  W.  Kingsley,  is  adopted  when  it  is  preferable  to  construct 
the  crown  between  the  visits  of  the  patient. 

In  utilizing  a  tooth  as  an  abutment  in  bridge-wTork  when  all 
or  nearly  all  of  the  occluding  surface  of  the  natural  crown  is 


ALL-GOLD  COLLAR  CROWNS  CONSTRUCTED  IN  SECTIONS.    95. 

present,  a  practical  method  of  construction  is  to  mark  the  out- 
line of  the  natural  crown  on  the  inner  surface  of  the  collar; 
then  remove  the  collar  and  trim  so  as  to  leave  a  border  of  about 
one-sixteenth  of  an  inch  outside  the  mark.     This  border  is  then 


wmmmmmmm 


P1 


thinned  with  a  corundum- wheel,  and  slit  as  seen  in  Fig.  195. 
The  collar  is  next  adjusted  on  the  crown,  and  the  slit  border 
bent  over  to  the  form  of  the  occluding  surface,  to  which  it  is 
burnished.     A  piece  of  pure  gold  plate,  about  No.  34  gauge,  is 


96 


ARTIFICIAL   CROWN-    AXD  RRIDGK-WOIIK. 


then  placed  on  the  occluding  surface  of  the  tooth  and  adapted  to 
ir  and  to  the  collar.  The  gold  may  be  first  struck  in  the  form 
of  a  cap  by  laying  it  on  a  block  of  lead  and  hammering  into  it 
a  die  corresponding  to  the  surface  of  the  tooth  to  be  crowned 
(Fiff.  196).  The  antagonizing  teeth  are  then  occluded  on  the 
gold,  which  is  therein-  pressed  to  form  to  articulate  with  the 
occluding  surfaces.  Enough  of  the  occluding  surface  of  the 
tooth  crowned  should  always  be  removed  to  allow  for  the  thick- 
ness of  the  gold  covering  its  surface.  The  collar  and  cap  are 
next  removed  and  soldered.  This  is  done  by  resting  the  collar 
on  the  cap,  which  is  held  by  a  pair  of  tweezers,  or  by  clamping 

Fig.  199. 


the  cap  and  collar  together  and  placing  the  solder  in  small  pieces 
around  the  collar  outside  the  cap,  at  A,  Fig.  197,  and  soldering 
by  holding  in  a  blue  gas  flame.  Only  sufficient  solder  should 
be  used  to  join  and  fill  the  seams,  so  that  it  will  not  interfere 
with  adjustment  on  the  natural  crown. 

The  methods  described  insure  a  perfect  occlusion  of  the  crown 
with  the  antagonizing  teeth.  In  the  absence  of  antagonizing 
teeth,  or  when  the  general  form  of  the  grinding-surface  permits 
it,  the  cap  can  be  struck  up  with  a  die  similar  to  the  one  shown 
in  Fig.  196.  The  cusps  are  then  filled  in,  and  the  edges  of  the 
inner  surface  of  the  cap  ground  level  on  the  side  of  a  corundum- 
wheel.  The  entire  circumference  of  the  edge  of  the  collar  is 
also  leveled,  and  the  cap  adjusted,  clamped,  and  soldered.     If 


ALL-GOLD  COLLAR  CROWNS  CONSTRUCTED  IN  SECTIONS.    97 

the  cusps  of  the  cap  are  filled  in  with  solder,  it  will  flow  down 
and  join  the  collar  on  the  inside  ;  if  with  gold  plate,  the  cap  and 
collar  must  be  joined  with  solder  either  on  the  inside  or  outside. 
Metallic  caps,  or  forms  of  the  occluding  surfaces  of  teeth  for 
use  in  constructing  crowns,  are  quickly  made  with  the  die-plate 
shown  in  Fig.  198,1  "  in  which 
are  four  groups  of  intaglio  dies 
representing,  with  distinctive 
correctness,  the  peculiar  cusps 
of  the  upper  and  lower  right 
and  left  bicuspids  and  molars. 
The  hubs  A,  B  (Fig.  199)  are  of 
the  sizes  shown,  and  are  made 
of  an  alloy  composed  of  tin  one 
part,  lead  four  parts,  melted 
together.     The  mold  C  should 

be  warmed,  the  metal  alloy  poured  in  every  hole,  and  the  over- 
flow wiped  off  just  before  the  metal  stiffens:  this  will  make  the 
butts  of  the  hubs  smooth  and  flat.  After  a  minute  or  two  the 
mold  may  he  reversed,  the  hubs  shaken  out,  and  the  casting 
process  continued  until  a  considerable  number  of  hubs  shall 
have  been  made.     In  Fig.  200  a  molar  hub  is  shown  in  place  on 

Ftg.  201. 


a  piece  of  Xo.  32  gold  plate,  which  lies  over  the  upper  right  first 
molar  die.  A  succession  of  blows  on  the  huh  with  a  four-pound 
smooth-face  hammer  will  drive  the  plate  into  the  die,  and,  at  the 
same  time,  spread  the  huh  metal  from  the  die  center  to  its  circum- 
ference, in  such  a  manner  that  the  plate  will  be  perfectly  struck 

1  Denial  ( ost7ios,  vol.  xzix,  page  482. 
8 


98 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


up  with  the  least  possible  risk  of  being  cracked.  The  flattened 
Jiub  is  seen  in  Fig.  201,  which  also  shows  at  D  the  obverse  of 
the  struck-up  hub,  and  at  E  the  cameo  of  the  struck-up  plate, 
having  every  cusp  and  depression  sharply  defined.  The  counter- 
die  plate  (Fig.  198)  is  made  of  a  very  hard  cast  metal,  which  will 


w 
r   o 


admit  of  the  striking  up  of  many  crown  plates  by  the  means 
described,  if  the  crown  plates  be  not  too  thick  and  stiff.  Of 
course  they  should  be  annealed  before  they  are  placed  over  the  die. 


ALL-GOLD  COLLAR  CROWNS  CONSTRUCTED  IN  SECTIONS.      99 

"  In  careful  hands  the  die-plate  should  give  clear  cusp  defini- 
tions after  years  of  use.  The  counter-die  plate  is  in  some  re- 
spects similar  to  a  stereotype  plate  for  printing,  and  the  struck 
impressions  on  two  strips  of  thin  plate  will  therefore  appear  as 
in  Fig.  202,  wherein  their  regular  order  is  noticeable,  as  seen 
from  the  cameo  surface  of  the  struck  plates. 

"  The  peculiar  action  of  the  hub  in  forming  first  the  center  of 
the  crown  plate,  and  spreading  from  the  center  outward,  as  the 
hub  is  shortened  under  the  hammer,  until  the  die  is  overspread 
by  the  plate  and  hub,  with  the  result  shown  in  Fig.  201,  is  an 
essential  feature  of  this  process  for  obtaining  easily  and  quickly 
the  superior  styles  of  coronal  cameos  shown.  If  a  cusp  or 
fissure  should  chance  to  crack  in  hubbing,  a  small  piece  of 
plate  may  be  struck  up  over  the  fissure,  and  then  soldered  to  the 
original  cap." 

The  methods  which  have  been  described  for  the  construction  of 
all-gold  bicuspid  and  molar  crowns  are  those  generally  adopted 
in  practice.  Of  others,  Dr.  J.  J.  R.  Patrick's  method1  consists 
of  first  forming  a  very  narrow  collar  and  telescoping  it  with  a 
seamless  cap  of  the  form  of  the  crown,  and  soldering  along  the 
line  of  the  cap  to  the  collar. 

Dr.  E.  P.  Brown's  method  is  to  make  or  select  a  metallic  die 
for  the  crown  to  be  formed ;  then  place  a  piece  of  pure  gold 
plate,  about  No.  31  gauge,  on  the  flat  surface  of  a  block  of  lead, 
and  gradually  stamp  the  die  downward  into  the  gold  to  about 
half  the  depth  of  the  intended  crown.  The  gold  is  then  re- 
moved, and  each  side  of  the  unswaged  portion  slit  and  adapted 
to  the  form  of  the  die,  the  full  length  of  the  crown,  which  is 
then  adjusted  in  the  mouth,  the  edges  of  the  gold  trimmed  to 
the  proper  form,  and  the  slits  soldered. 

Dr.  M.  Rynear's  crown  is  of  the  same  general  character  and 
is  constructed  in  the  same  manner  as  Dr.  Brown's,  except  that  a 
seamless  cap  is  used  to  form  the  crown,  instead  of  the  flat  piece 
of  plate  used  by  Dr.  Brown. 

Dr.   T.   Fillebrown's  method   of  constructing  a  bicuspid   or 


'Dr.  Patrick's  crown-work  methods  and  the  principles  upon  which  they  are 
based  are  set  forth  in  a  paper  published  in  the  Dental  Cosmos  for  October,  1888, 
page  706. 


100  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

molar  all-gold  crown  when  The  sides  of  the  natural  tooth  have 
Ik >r.  tor  some  reason,  been  reduced  in  dimensions  to  that  of  the 
cervix,  is  to  first  form  and  lit  a  full-sized  collar  of  thin  pure  gold, 
then  adapt  and  solder  over  it  a  second  and  narrower  collar  of 
Fig.  203.  thin  22-carat  gold  plate,  extending  only  from  the  oc- 
cluding surface  about  half  the  distance  to  the  gum- 
margin.  The  cap  for  occluding  surface  is  then  added 
in  the  usual  manner.  AVhen  the  finished  crown  is 
cemented  in  position,  and  while  the  cement  is  yet 
quite  soft,  a  burnisher  is  passed  around  the  neck  of 
the  crown,  and  the  pure  gold  forming  that  part,  as 
represented  by  A,  Fig.  203,  is  brought  close  against  the  neck  of 
the  natural  tooth.  This  method  of  forming  a  gold  crown  can 
be  advantageously  practiced  in  cases  of  bridge-work. 

AUrGold  Crowns  for  the  Incisors  ami  Cus  jii<Js. — When  the  teeth 
are  short  and  the  incisive  edges  flat  or  abraded,  and  the  all-gold 
crown  required  is  to  correspond  in  form  or  be  only  a  little 
longer,  the  gold  collar,  after  being  fitted  to  the  tooth,  is  slit  on 
the  palatal  or  lingual  side,  and  bent  and  burnished  to  it.  The 
collar  is  then  removed  and  the  seams  soldered  together.  This 
is  best  done  by  holding  the  collar  in  a  Bunsen  gas  flame,  with 
the  solder  placed  in  position  in  very  small  pieces,  and  only  suf- 
ficient in  quantity  to  join  the  seams.  The  collar  is  next  ad- 
justed to  the  tooth,  and  the  gold  at  the  incisive  edge  trimmed 
even.  A  fiat,  thick  piece  of  gold  plate  or  clasp-material  is  sol- 
dered  across  the  incisive  edge  to  form  and  inclose  that  portion 
of  the  crown. 

When  the  crown  required  is  of  the  normal  form,  the  collar 

when  properly  fitted  should  be  removed  at  the  palatal  section, 

Fig.  204.  as  shown  in  Fig.  204.     The  edge  of  the  gold  is  then 

^^     chamfered,  and  bent  and  burnished  over  the  incisive 

fm    edge  and  sides,  close  to  the  natural  tooth.     To  this  open 

section  is  next  adapted  a  flat  piece  of  gold  plate,  the 

^*    collar  is  removed,  and  the  parts  are  soldered  together. 

Fluxed  solder  filings  can  be  melted  in  the  interior  of  the  incisive 

edge  to  increase  its  thickness. 

A  fusible  metal  die  of  the  natural  tooth  is  a  material  aid  in 
the  construction  of  this  style  of  crown. 


ALL-GOLD  COLLAR  CROWNS  CONSTRUCTED  IN  SECTIONS.    101 

Fig.  205  represents  a  case  of  abrasion  of  the  lower  teeth,  to 
which  all-gold  crowns  have  been  applied,  as  shown  in  Fig.  206. 
In  such  cases,  owing  to  the  aggression  of  the  occluding  teeth, 

Fig.  205. 


Fig.  200. 


the  cap  forming  the  occluding  surface  should  be  constructed  of 
heavy  gold  and  platinum  plate.  An  artificial  plate  replaces  the 
upper  teeth. 


CHAPTER   IX. 


THE  GOLD  SEAMLESS  CAP  CROWN. 


This  method  consists  in  the  use  of  a  gold  seamless  cap  for  the 
construction  of  the  required  root  cap  or  crown. 

INCISORS,   CUSPIDS,   AND   BICUSPIDS,  WITH    PORCELAIN 

FRONTS. 

Incisor,  cuspid,  and  bicuspid  crowns  with  porcelain  fronts  are 
constructed  by  this  method  as  follows :  The  natural  crown  is 
ground  down  to  within  about  one-eighth  of  an  inch  of  the  gum 
at  the  palatal  wall,  or  enough  to  clear  the  antagonizing  teeth 
when  occluded,  and  slanting  from  the  posterior  edge  of  the 
pulp-chamber  to  the  cervico-labial  edge  of  the  gum  and  slightly 
under  its  margin  if  it  is  desirable  to  conceal  the  joining  of  the 
crown  with  the  root.  The  sides  are  shaped  the  same  as  for  a 
collar  crown  (Fig.  207).  A  die  of  the  end  of  the  root  is  then 
made.  For  this  purpose  an  impression  of  the  part  is  taken  with 
gutta-percha  on  the  end  of  a  piece  of  wood 
trimmed  to  the  proper  size,  or  by  placing 
some  plaster  of  Paris  with  a  little  sulphate 
of  potassium,  mixed  to  the  consistence  of  a 
paste,  in  a  tube  formed  of  a  strip  of  copper 
about  one  and  one-half  inches  in  length  and 
three-eighths  of  an  inch  in  diameter,  cut  out 
on  the  sides  to  the  depth  of  half  an  inch, 
with  the  flange  for  the  palatal  side  shortened  1 
(Fig.  208).  The  impression  thus  taken  will 
be  confined  almost  entirely  to  the  end  of  the 
root  to  be  capped.  When  gutta-percha  is  used,  it  is  cooled 
and  dried  perfectly.     A  strip  of  paper  is  tied  around  the  wood 

1  See  article  on  "  Molds  and  Dies,"  which  describes  how  to  make  a  tube  without 
soldering. 
102 


Fig.  207.     Fig.  208. 


THE  GOLD  SEAMLESS  CAP  CROWN. 


103 


or  tube,  and  a  die  cast  with  the  fusible  metal.  The  cooling  is 
hastened  by  immersion  in  a  glass  of  water.  AVhen  cool,  the  die 
is  removed  from  the  mold,  and  the  metal  is  trimmed,  with  file 
and  chisel,  a  little  deeper  than  the  gum  has  permitted  the  im- 
pression of  the  root  to  be  taken,  and  without  altering  the  form 
of  the  end  of  the  root  (Fig.  209).  A  counter-die  is  then  made 
by  punching  a  hole  in  the  surface  of  a  block  of  pure  lead,  and 
with  a  few  blows  of  a  hammer  driving  the  die  into  it. 

A  cap  of  gold  can  be  formed  by  placing  a  piece  of  gold  plate 
(preferably  pure,  Xo.  32  U.  S.  standard  gauge)  of  suitable  size 
upon  a  block  of  lead,  and  with  an  oval-shaped  punch  one-fourth  of 
an  inch  in  diameter  gradually  driving  it  into  the  lead  until  the  gold 


Fig.  209. 


Fig.  210. 


Fig.  212. 


Fig.  211. 


has  assumed  the  shape  of  a  cap  about  a  quarter-inch  in  depth  (A, 
Fig.  209).  The  gold  should  be  withdrawn  from  under  the  punch 
and  annealed  several  times  during  the  process.  ( Japs  can  also  be 
made  with  a  stamping-press  such  as  was  introduced  by  Dr.  J.  J. 
R.  Patrick,  of  Belleville,  Til.     (See  page  110.) 

The  cap  is  then  annealed  and  swaged  on  the  die  to  the  form 
of  the  end  of  the  root  (B,  Fig.  209).  The  palatal  portion  of  the 
cap  should  be  allowed  to  go  well  up  under  the  free  edge  of  the 
gum,  and  at  the  cervico-labial  edge  it  can  be,  if  preferred,  cut  out 
to  the  edge  of  the  root.  In  the  process  of  adjustment,  the  edges 
which  fit  under  the   irum  should  be  marked  and  trimmed  as 


104  ARTIFICIAL    CROWN-  AXD  BRIDGE- WORK. 

directed  in  describing  the  construction  of  a  collar  crown,  and 
then  burnished  close  to  the  sides  of  the  root  and  into  the  orifice 
of  the  root-canal,  forming  a  perfect-fitting  seamless  cap  (Fig. 
210).  An  iridio-platinum  pin  is  then  fitted  in  the  root-canal  and 
soldered  to  the  cap  (Fig.  211),  or  afterward  adjusted  as  in  the 
construction  of  the  gold  collar  crown  with  porcelain  front  (page 
86),  with  which  operation  the  remainder  of  the  process  ot 
construction  is  identical.  Fig.  212  represents  the  completed 
crown. 

The  advantages  of  this  style  of  crown  are,  simplicity,  as  the 
formation  of  a  collar  is  avoided,  and  strength,  as  a  large  portion 
of  the  natural  crown  can  be  left  at  the  palatal  side.  This  affords 
a  stronger  and  more  reliable  foundation  than  can  be  obtained  at 
any  other  point,  as  the  direction  of  the  force  in  mastication  is 
forward  at  an  angle  with  the  line  of  the  root,  and  although  the 
gold  of  the  cap,  where  it  encircles  the  root  at  the  cervico-labial 
edge,  is  entirely  removed,  the  crown  is  still  held  securely. 

In  a  paper  on  the  subject  of  preserving  and  utilizing  this  part 
of  the  tooth,  Dr.  W.  F.  Litch,  of  Philadelphia,  describes  a 
crowning  operation,1  in  which  he  constructed  the  cap  of  platinum 
by  slitting  a  piece  of  the  plate  in  a  number  of  places,  adapting  it 
to  the  form  of  the  end  of  the  root,  and  then  soldering  the  whole 
together. 

This  operation  is  not,  however,  so  easily  or  so  satisfactorily 
performed  as  the  method  above  described,  in  which  platinum,  if 
desired,  can  be  used  instead  of  gold,  and  the  soldering  done  with 
22-  or  24-carat  gold.  In  some  respects  pure  platinum  is  prefer- 
able to  gold  in  capping  roots,  as  it  is  less  likely  to  be  affected  by 
the  secretions  of  the  mouth. 

ALL-GOLD    SEAMLESS    BICUSPIDS    AND    MOLARS. 

All-gold  seamless  crowns  for  bicuspids  and  molars  that  will 
accurately  fit  the  natural  crown  and  root,  and  occlude  properly 
with  the  antagonizing  teeth,  are  easily  and  quickly  formed,  if 
sufficient  of  the  natural  crown  remains  to  admit  of  temporary 
restoration  of  its  contour  with  gutta-percha  or  any  other  suitable 
plastic  material.    When  this  has  been  done,  an  impression  of  the 

1  Dental  Cosmos,  vol.  xxv,  No.  9,  page  449 


THE  GOLD  SEAMLESS  CAP  CROWN.  1Q.3 

restored  tooth  is  taken  in  plaster  or  gutta-percha  in  a  tube,  as 
explained  on  page  102,  and  a  die  then  formed  of  fusible  alloy; 
or  a  plaster  model  can  be  made  from  an  impression  of  the  tooth 
taken  in  wax,  and  a  mold  obtained  from  the  model  with  moldine. 
The  preparation  and  shaping  of  the  natural  crown  to  receive 
the  artificial  crown  can  then  be  proceeded  with.  Where  the 
natural  crown  is  very  badly  decayed  or  broken  down  and  the 
method  just  described  is  not  practicable,  the  portion  of  the 
natural  crown  or  root  remaining  should  be  shaped  and  prepared 
to  receive  an  artificial  crown.  Then  the  form  of  the  cervix  is 
ascertained  with  a  wire  as  described  on  page  81,  and  an  impres- 
sion of  the  parts  taken  in  wax,  and  the  wire  form,  the  twisted 
ends  having  been  shortened,  is  carefully  adjusted  on  the  wax  at 
the  cervical  line.     The  plaster  model,  when  made,  will  show  the 

Fig.  213.  Fig.  214. 


wire  slightly  imbedded  in  the  plaster.  The  plaster  >liould  be 
trimmed  to  the  inner  edge  of  the  wire,  as  that  represents  tin- 
exact  form  of  the  root  (Fig.  213). 

Another  method  is  to  encircle  and  adapt  to  the  form  of  the 
root  a  strip  of  annealed  copper,  No.  35  standard  gauge,  about 
one-eighth  of  an  inch  wide,  and  mark  the  end  of  the  overlap. 
The  copper  is  then  removed,  the  ends  joined  with  an  atom  of 
solder,  and  the  copper  adjusted  on  the  root.  An  impression  is 
next  taken  with  plaster,  in  which  the  copper  band  is  removed  in 
position.  A  model  made  from  this  impression,  after  the  copper 
is  removed,  presents  the  exact  form  of  the  root. 

From  a  "bite"  taken  in  wax  a  plaster  articulation  is  then  made 
to  the  model.  A  hole  is  then  drilled  in  the  center  of  the  form 
of  the  root  on  the  model  to  be  crowned.     In  this  hole,  and  over 


106 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


the  end  of  the  root,  a  ball  of  soft  plaster,  slightly  colored  with 
carmine,  is  placed,  and  the  teeth  of  the  articulation,  covered 
with  tin  foil,  closed  on  it.  This,  on  separation,  gives  the  outline 
of  the  form  of  the  grinding-surface  for  the  crown.  The  sides  of 
the  plaster  are  then  trimmed  to  the  form  of  the  crown,  and  the 
whole  carved  in  detail  (Fig.  214).  As  the  crown  will  always 
stamp  larger  in  circumference  than  the  die,  in  proportion  to 
the  thickness  of  the  gold  used,  an  allowance  must  be  made 
by  trimming  off  a  proportionate  amount  of  the  surface  of  the 
model;  otherwise  the  outer  surface  of  the  crown  will  be  larger 
than  is  desired.  When  the  plaster  model  for  the  crown  is  made, 
it  is  separated  from  the  rest  of  the  model  at  the  dotted  line  seen 
in  Fig.  214,  and  trimmed  in  the  form  shown  by  the  cast  A, 
Fig.  215.     From  this  model  the  die  is  made  in  a  tube  with 


Fig.  215. 


Fig.  216. 


Fig.  217. 


Fig.  218. 


moldine  and  fusible  metal  as  described  at  page  102. 
The  cast  should  always  be  lengthened  at  the  neck, 
so  that  the  crown  when  constructed  shall  have  a 
surplus  in  depth  of  gold  to  allow  for  any  trimming  or  shaping  ot 
the  collar  that  may  be  required.  The  counter-die  (B,  Fig.  215) 
is  made  by  punching  a  hole  in  a  block  of  lead  and  hammering 
the  die  into  it.  The  crown,  which  is  usually  formed  of  pure 
gold,  or  gold  slightly  alloyed,  or  gold  lined  with  very  thin  platinum 
from  Xo.  30  to  Xo.  32  gauge,  is  then  made  by  first  stamping  a 
piece  of  plate  (see  page  108)  in  the  form  ot  a  cap  of  gold  (A,  Fig. 
216).  This  cap  is  then  placed  on  the  cast,  and  with  the  aid  of  the 
counter-die  (B,  Fig.  215)  swaged  to  the  form  of  the  crown  B, 
Fig.  216.  A  piece  of  kid  leather  should  be  used  to  cover  and 
protect  the  gold  from  the  lead,  and  facilitate  its  removal  from 


THE  GOLD  SEAMLESS  CAP  CROWN. 


107 


the  counter-die.  An  allowance  for  the  thickness  of  the  leather 
must  be  first  made,  by  driving  it,  without  the  gold  on  the  cast, 
into  the  counter-die  to  enlarge  it,  If  this  is  not  done,  the  gold  is 
liable  to  be  torn  in  the  swaging. 

Dr.  C.  B.  Parker's  method  of  stamping  the  piece  of  gold 
plate  is  to  form  two  dies  of  the  recpuired  crown, — the  first  with 
a  cone-shaped  neck  up  to  the  grinding-surface  (Fig.  217),  and 
the  second  straight  on  the  sides  (Fig.  218).  The  gold  is  stamped 
up  on  the  first  die,  giving4  the  grinding-surface,  but  leaving  the 
sides  flaring,  and  then  on  the  second  to  straighten  the  sides. 

Cuspid  crowns  from  which  a  portion  of  the  gold  on  the  labial 
aspect  is  to  be  removed,  or  which  are  to  be  used  entire  as  a 
support  for  bridge-work,  can  usually  be  advantageously  formed 

Fig.  219. 


with  a  seamless  cap  (Fig.  219).  The  necks  of  these  crowns  can 
be  contracted  in  fitting  in  a  contracting  plate,  or  slit,  lapped,  and 
soldered,  should  the  case  so  require.  (For  details  of  process  of 
adjustment  and  insertion,  see  "  Adjustment  of  Seamless  Contour 
<  Jrowns,"  page  111.) 


CHAPTER    X. 

GOLD   SEAMLESS   CONTOUR   CROWNS.1 

The  artistic  requirement  of  all-gold  crown-work  is,  that  it 
shall  reproduce  the  anatomical  contour  of  the  natural  teeth. 
This  is  usually  accomplished  by  melting  solder  on  the  collar  and 
then  trimming  it  to  the  form  of  the  crown.  A  preferable 
method  is  to  shape  the  metal  forming  the  sides  of  the  crown  by 
swaging.  This  is  easily  done  in  a  crown  formed  in  sections,  but 
a  special  process  is  required  in  the  construction  of  seamless 
crowns. 

A  contour  crown  can  be  made  by  placing  a  seamless  cap  on  a 
sectional  die  or  mandrel  of  the  shape  of  the  tooth,  first  swaging 


Fig.  220. 


Fig.  221. 


Fig.  222. 


the  grinding-surface  on  the  mandrel  and  then  stamping  down- 
ward on  the  straight  sides  of  the  crown  with  a  cap  fitted  to  the 
shank  part  of  the  mandrel.  But  such  a  process,  like  many 
others,  is  too  complicated  to  be  of  any  use  to  the  dental  prac- 
titioner. The  sectional  mold  method  here  presented  is  simple, 
practical,  and  general  in  its  application. 

To  describe  and  illustrate  the  process,  we  will  take  one  of 
the  most  difficult  crowns  to  construct, — a  superior  molar  (Fig. 

1  Gold  crowns  of  this  form  are  now  made  and  sold  as  the  "  Evans  Gold  Crowns." 
The  Evans  gold  non-fu6ible  crown  is  lined  with  platinum  on  the  interior  of  the  oc- 
cluding surface  and  part  of  the  sides,  to  prevent  melting  the  gold  in  soldering. 

108 


GOLD  SEAMLESS  COXTOUR  CROWyS. 


109 


220).  A  natural  tooth,  or  one  made  of  plaster,  is  used  as  a 
model.  From  this  a  sectional  mold  is  made,  as  illustrated  in 
Figs.  221  and  222,  in  Babbitt's  metal,  zinc,  or  fusible  alloy. 
Into  the  mold  a  cap  of  gold  (Fig.  223)  23  to  24  carats  fine,  30 
to  32  gauge,  is  adjusted,  fitting  tightly  the  orifice  of  the  closed 
mold.  The  mold  is  placed  in  a  vise,  the  cap  expanded  to  the 
general  form  of  the  mold  by  hammering  into  it  a  mass  of 
cotton,  and  then  swaged  more  in  detail  to  the  form,  and  with 
a  wood  point  or  a  burnisher  revolved  by  the  dental  engine 
burnished  into  every  part  of  the  mold  (Fig.  224).  To  facilitate 
the  process,  the  mold  should  be  frequently  opened,  and  the  gold 
annealed.  Fig.  225  represents  the  completed  crown.  These 
results  can  be  secured  by  other  styles  of  molds :  Fig.  224  illus- 
trates one,  but  the  principle  is  the  same. 


Fig.  225. 





Another  method  is  to  form  a  fusible-metal  die  of  the  tooth  to 
be  crowned,  and.  after  having  stamped  the  grinding-surface  of 
the  crown,  to  reverse  and  swage  the  sides  close  to  the  die ;  the 
crown  is  then  relieved  of  the  core  (die)  by  heating  to  the  melting 
point  of  the  fusible  metal  and  pouring  it  out. 

For  practical  use,  a  variety  of  molds  is  required,  made  from 
natural  teeth  of  different  sizes  and  average  forms  to  serve  in 
corresponding  cases.  The  crowns  can  be  contracted  at  the  neck 
more  than  their  size  and  contour  call  for,  so  that  the  gold  will 
acl  as  a  tight-fitting  band  which  will  expand  to  the  form  of  the 
root  as  the  crown  is  pressed  up  in  the  process  of  adjustment. 

Caps  of  metal  can  be  made  in  different  sizes  and  kept  on  hand 
for  use  in  this  and  other  styles  of  crown-work  by  means  of  a 
machine  (Fig.  22G),  which  in  principle   is  such  as  is  used  by 


110 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


jewelers  for  forming  cap-shaped  pieces  of  gold,  and  in  factories 
for  making  copper  cartridges.    The  gold  plate,  cut  into  circular 


Fig.  226. 


The  form  of  stamping  machine  introduced  by  Dr.  J.  J.  R.  Patrick. 

pieces,  is  pressed  through  a  steel  die-plate,  with  punches  gauged 

to  the  holes;  at  each  punch  a  small  portion  of  the  gold  is  turned 

Fig.  227. 


Fig.  228. 


e    e   e  0 


©  ©  ©® 


over,  thus  preventing  its  lapping  or  creasing  (Fig. 
227).  Repeated  annealing  of  the  metal  is  very 
necessary  in  this  process. 

Methods  of  Contouring  Crowns  constructed  in  Sec- 
tions.— In  constructing  a  crown  in  sections,  the  collar  can  be 
first  formed  on  a  mandrel,  then  placed  in  a  mold,  and  burnished 


GOLD  SEAMLESS  CONTOUR  CROWNS. 


Ill 


to  the  shape  of  the  sides.     The  process  of  its  adjustment  to  the 
neck  of  the  root  is  then  continued  in  the  usual  manner. 

Another  method  is  to  stamp  or  burnish  up  the  collar  on  a  die 
representing  the  upper  sections  of  a  tooth,  designated  as  the 
middle  and  cervical  third  (Fig.  228).  After  contouring  the 
collar,  the  cap  is  adjusted  and  soldered  on.  With  a  metallic 
stamping  plate  (see  page  95)  these  caps  are  quickly  made 

ADJUSTMENT   OF    SEAMLESS    CONTOUR   CROWNS. 

A  superior  molar — one  of  the  most  difficult  teeth  to  operate 
on — will  serve  as  a  typical  case  to  illustrate  this  process.  The 
crown  or  root  is  first  shaped  and  if  necessary  built  down  with 
amalgam,  straight,  or  tapering  slightly  on  its  sides  toward  the 
occluding  surface,  as  described  at  page  35. 

How  to  Select  a  Suitable  Crown. — The  width,  of  the  crown  re- 
quired from  the  anterior  to  the  posterior  sides  of  the  occluding 
surface  is  first  obtained  by  measurement  with  a  piece  of  card- 
board or  thin  copper  plate,  as  shown  at 
A,  Fig.  229.  The  measurement  can  be 
taken  direct  from  the  mouth,  or  more  con- 
veniently from  a  small  plaster  cast  made 
from  a  correct  impression  of  the  prepared 
crown  or  root  and  the  two  approximal  teeth. 
This  measurement  can  also  be  taken  by 
means  of  tweezers  with  a  set-screw  (Fig.  230.)  AVith  this  meas- 
urement as  a  guide,  the  proper-sized  occluding  surface  is  readily 
found  by  comparison  with  the  dimensions  of  the  various  crowns 
as  shown  on  the  printed  chart  of  the  crowns  (0,  Figs.  231  and 

232). 

Fig.  230. 


Fig.  229. 


Tweezers  with  set-screw  to  use  as  calipers. 


The  size  of  the  neck  can  be  calculated  by  the  eye,  or  by  taking 
the  dimensions  with  a  piece  of  fine  wire  (Fig.  235),  pressing  the 
wire  on  the  surface  of  a  piece  of  sheet  wax,  and  then  comparing 
with  the  impression  the  necks  of  the  gold  crowns. 


112 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


In  making  a  selection,  it  should  be  borne  in  mind  that  the 
cervix  of  the  gold  crown  should  preferably  be  smaller  than 
larger,  as  it  can  always  be  easily  expanded,  while  its  contraction 
is  difficult.  It  is  not  essential  that  the  curve  of  the  collar  shall 
correspond  with  that  of  the  tooth,  as  the  gold  will  readily  take 
the  proper  shape  as  the  crown  is  adjusted. 


Method  of  Adjusting  the  Grown. — 1.  Anneal  the  crown  selected, 
and  slip  it  over  the  end  of  the  natural  crown  or  root  and  gently 
press  or  work  it  upward — the  gold  of  the  collar  will  expand  to 
the  form  of  the  root  in  the  operation — until  the  edge  meets  the 
margin  of  the  gum  (A,  Fig.  233). 

2.  Mark  a  line  (B)  on  the  gold  parallel  with  the  margin  of  the 
gum. 

3.  Remove  and  trim  to  this  line  (A,  Fig.  236).  If  necessary, 
repeat  the  marking  and  trimming  until  the  edge  meets  the  gum 
evenly. 

4.  Bevel  the  edge  of  the  gold,  readjust  the  crown  and  press  it 
up  until  the  edge  of  the  collar  passes  under  the  margin  of  the 
gum,  and,  if  the  occlusion  is  correct,  burnish  the  gold  to  the 
cervix. 

Jo  Expand  the  Collar  and  Crown. — If  the  collar  of  the  crown 
needs  enlargement,  it  is  easily  and  most  properly  accomplished 


GOLD  SEAMLESS  CONTOUR  CROWNS. 


113 


with  crown  expanders  (shown  in  miniature  form  in  Fig.  237), 
the  points  of  which  should  he  introduced  at  first  just  within  the 
edge  of  the  neck,  and  the  gold  spread  sufficiently  to  allow  it  to 
fit  over  the  end  of  the  natural  crown  or  root,  the  process  of  ex- 


Fig.  234. 


Fig.  235. 


Fig.  236. 


Fig.  237. 


Fig.  238. 


pansion  being  gradually  continued  as  the  crown  is  brought  into 
position.  By  proceeding  in  this  manner  too  great  expansion  is 
avoided. 

If  the  entire  crown  needs  enlargement,  it  is  best  done  by  soft- 
ening a  mass  of  gutta-percha  of  about  the  same  size  as  the 
crown  upon  the  closed  ends  of  a  pair  of  expanding  or  clamp 
forceps,  which  are  heated  for  the  purpose.  The  forceps  points 
with  the  gutta-percha  are  then  introduced  inside  the  collar  of  the 
crown,  which  should  be  moistened 
to  prevent  adhesion.  The  gutta- 
percha is  next  withdrawn,  hardened 
in  cold  water,  and  cut  through  the 
center  between  the  points  of  the  for- 
ceps. This  makes  practically  an  ex- 
panding sectional  mandrel  with 
which  the  crown  can  be  enlarged  according  to 
the  position  in  which  the  forceps  were  introduced 
(Fig.  238). 

To  expand  the  crown  without  enlarging  the 
neck,  trim  off  the  gutta-percha  on  the  forceps  at 
the  neck. 

The  naked  points  of  an  ordinary  clamp  forceps 
can  sometimes  be  used  to  advantage  to  expand  a 
portion  of  the  coronal  section  of  the  crown. 

To  Alter  a  Side. —  77/e  contour  of  <>ih  <>r  both  sides  <-,n,  be  de- 
pressed andthe  crown  thus  narrowed  by  introducing  the  points  of  a 
crown  expander  or  some  tool  that  will  fit  loosely  inside  the  crown, 

9 


114 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


then  steadying  the  crown  with  the  fingers,  as  shown  in  Fig.  239, 
and  tapping  the  sides  to  be  reduced  with  the  flat  end  of  a  rivet- 
ing hammer.  This  is  necessary  when  the  contour  or  the  side  of  a 
crown  presst  son  an  adjoining  tooth,  and  the  crown  is  thus  prevented 
from  coming  in  proper  position. 

To  Alter  tfu  Shapt  of  a  Portion  of  tin:  Collar  or  Side  of  a  Crown. — 
Slip  the  crown  over  the  point  of  an  anvil,  or  the  end  of  a  pair 
of  expanders,  or  a  small  round-handled  instrument  held  in  a 
vise,  and  then  tap  the  part  to  be  altered  with  the  flat  end  of  a 
riveting  hammer  to  the  form  desired. 

To  Alter  the  Occluding  Surface. — Before  the  crown  is  pressed  up 
to  its  apparently  proper  position,  the  occlusion  should  be  ex- 
amined, and  calculations  carefully  made  to  obviate  any  defects 


Fig.  239. 


Fig.  240. 


of  articulation,  which  can  be  readily  corrected  at  this  stage  by 
proper  manipulation  of  the  crown.  Any  necessary  change  in 
the  form  of  the  occluding  surface  can  be  made  with  the  crown 
in  position  on  the  tooth,  by  means  of  an  instrument  tapped  by 
the  mallet;  or  by  removing  the  crown,  placing  it  over  the  closed 
points  of  an  expander,  and  tapping  and  burnishing  the  part;  or 
by  holding  the  crown  between  the  thumb  and  forefinger  with 
the  edge  of  the  collar  resting  on  the  side  of  the  next  finger, 
wThich  when  necessary  can  be  protected  with  a  napkin,  and  then 
tapping  the  gold  with  the  point  of  a  riveting  hammer  (Fig.  240). 

The  occluding  of  the  antagonizing  teeth  on  the  crown  by  the 
patient  will  assist  and  complete  the  process  of  articulation. 

To  Contract  the  Neck. — Slightly  bend  in  the  edge  of  the  gold  at 
the  neck  with  narrow-beaked  pliers,  and   holding  the  crown 


GOLD  SEAMLESS  CONTOUR  CROWNS. 


115 


Fig.  241. 


evenly  and  firmly  between  the  fingers,  as  shown  in  Fig.  241, 
burnish  the  sides  of  the  neck  section  inward  around  the  entire 
circumference  of  tbe  crown. 

To  Considerably  Contract  a  Orovm. — Slit  the  gold  longitudinally 
at  the  palatal  or  lingual  side  its  full  length  to  the  grinding-sur- 
face,  bevel  off  the  edge  to  lap  under,  con- 
tract the  crown,  readjust  to  the  tooth, 
remove,  place  the  smallest  quantity  of 
dampened  fluxed  solder  filings  in  tin- 
seam  on  the  inside  of  the  crown  only,  and 
solder  by  holding  in  an  alcohol  flame. 
Then  proceed  with  the  further  adjust- 
ment of  the  crown. 

The  outside  line  of  the  seam  can  be 
stoned  off  and  polished  after  the  crown 
has  been  fitted,  and  additionally  soldered 
to  strengthen  the  sides  orgrinding-surface. 

Strengthening  Seamless  Gold  Contour  Crowns. — Additional 
strength  and  stiffness  can  be  given  to  seamless  gold  crowns, 
when  desired,  in  several  ways.  The  liability  of  melting  the 
gold  which  forms  the  sides  of  the  crown  in  the  operation  has, 
with  some,  been  the  principal  objection  to  their  use.  This, 
however,  can  be  avoided. 

When  the  crown  has  been  properly  adjusted,  dampen  the 
inner  surface  with  a  piece  of  wet  cotton  on  the  point  of  an  in- 
strument; place  in  the  interior  a  quantity  of  fluxed  solder  filings 
(solder  filings  mixed  with  Parr's  flux  or  pulverized  vitrified 
borax) ;  place  the  finger  over  the  open  end  of  the  crown,  invert, 
and  shake  well.  A  portion  of  the  solder  filings  will  adhere 
evenly  all  over  the  wet  surface.  The  surplus  is  allowed  to  drop 
out  by  removing  the  finger.  Then  gradually  and  uniformly 
heat  the  crown  by  holding  it  with  tweezers  in  an  alcohol  flame 
(not  gas)  until  the  solder  fuses,  when  it  will  flow  evenly  over  the 
surface  of  the  gold  without  materially  altering  the  general  form. 
The  crown  should  be  held  in  such  a  position  that  a  full  view  of 
the  interior  is  presented  and  the  melting  of  the  solder  rendered 
visible,  which  will  occur  at  a  red  heat. 

An  extra  quantity  of  the  solder  filings  can  be  placed  in  the 


116 


ARTIFICIAL  CROWN-  AXD  BRIDGE-WORK. 


interior  of  the  cusps  with  a  spoon-shaped  excavator  to  additionally 
fill  or  strengthen  them  if  found  necessary. 

When  a  Bunsen  gas  flame  is  used  instead  of  an  alcohol  flame, 
the  grinding-surface  and  sides  of  the  crown  should  be  first  coated 
with  whiting.  This  is  easily  done  by  dipping  the  crown  into  a 
cream-like  mixture  of  whiting  just  before  inserting  it  in  the  flame. 
The  moisture  in  the  whiting  should  be  first  slowly  evaporated 
by  heating  up  gradually.  Great  care  must  be  exercised  in  the 
use  of  a  gas  flame  to  avoid  melting  the  crown.  The  crown 
should  be  watched,  and  instantly  removed  as  soon  as  the  solder 
fuses  and  flows. 

If  too  much  solder  has  been  applied  at  any  point,  it  can  be 
trimmed  and  smoothed  with  corundum  melted  on  to  an  old 
engine  bur-point.  Always  boil  the  crown  in  acid  to  remove  the 
flux.  The  removal  of  flux  from  the  inner  surface  of  the  crown 
is  absolutely  necessary  if  you  intend  to  use  it  in  bridge-work,  as 
solder  will  have  to  be  melted  on  the  outside. 

To  repair  a  hole  melted  in  any  kind  of  a  gold  crown,  place  a 
piece  of  soft  wax  in  the  aperture  on  the  outside  of  the  crown, 
adapt  on  the  inside  close  against  the  gold  a  piece  of  platinum 
foil,  somewhat  larger  than  the  aperture,  so  that  it  will  adhere  to 
the  wax.  Fill  the  interior  of  the  crown  with  investing  material, 
and  flow  a  little  solder  over  the  surface  of  the  platinum  and 
gold  on  the  outside  of  the  crown. 

Gold  seamless  crowns  can  also  be  strength- 
ened or  filled  with  solder,  or  even  18-  or  20- 
carat  gold  plate,  by  investing  the  outside  sur- 
face in  plaster  and  marble-dast  (Fig.  242),  and 
then  with  a  small  flame  of  the  carbo-oxyhy- 
drogen  blow-pipe,  not  over  one-half  an  inch  in 
Length,  introduced  inside  of  the  crown,  melt 
and  flow  the  solder  or  gold  plate  over  any 
portion  or  even  all  of  the  surface  of  the  gold. 
The  crown,  if  formed  of  gold  with  a  thin  lining 
of  platinum,  can  be  soldered  by  either  method  with  little  danger 
of  being  melted. 

Supporting  th  Crown. — In  crowning  teeth  with  living  pulps 
there  is  sufficient  of  the  natural  crown  present  to  afford  a  secure 


Fig.  242. 


GOLD  SEAMLESS  CONTOUR  CROWNS.  11  7 

foundation  and  attachment  for  the  artificial  crown,  as  is  also  the 
case  with  many  teeth  that  are  pulpless;  but  in  badly  broken- 
down  crowns,  or  where  only  the  root  is  present,  a  metallic  pin 
or  post  should  be  inserted  in  the  root,  and  the  part 
built  down  with  amalgam  to  a  form  which  will  afford 
secure  support  and  attachmentto  the  artificial  crown, 
and  facilitate  its  adjustment.     (See  tl  Special  Prepa- 
ration of  Badly  Decayed  Teeth  or  Roots,"  page  36.) 

In  many  cases  the  required  support  for  the  crown 
can  be  secured  by  means  of  a  screw  (Fig.  243). 
A  How  screw  or  a  post  of  silver  wire  is  inserted  in 
the  root-canal  A  (see  page  49).  Amalgam  is  then 
} tacked  in  the  lower  section  of  the  artificial  crown, 
C,  to  the  line  B,  and  into  the  amalgam  the  screw  is  pressed. 
Amalgam  which  has  been  put  in  a  piece  of  chamois  and  the  mer- 
cury pressed  out  with  a  pair  of  pliers  until  it  is  in  the  condition 
termed  "  dry"  will  adhere  to  the  gold  without  affecting  it.  The 
amalgam  is  first  placed  in  the  crown  slightly  in  excess  of  the 
amount  required,  and  the  crown  adjusted,  removed,  and  the 
surplus  scraped  out.  This  process  is  continued  until  the  screw 
or  the  crown  section  of  the  natural  tooth  forms  an  indentation 
in  the  amalgam,  which  it  will  fit  when  the  crown  is  cemented  on. 
The  vent  for  the  escape  of  air  and  surplus  cement — which  should 
always  be  put  in  perfect-fitting  crowns  and  afterward  filled  with 
gold  or  amalgam — should  be  in  the  line  of  the  indentation  in 
the  amalgam,  with  which  it  must  connect  (D).  (For  process  of 
cementation,  see  article  on  "Insertion  and  Cementation.") 

These  crowns  can  be  inserted  in  an  easy  and  inexpensive  man- 
ner by  filling  in  the  lower  section  of  the  crown  with  amalgam 
instead  of  gold,  and  allowing  the  head  of  the  screw  or  the  nat- 
ural crown  to  indent  the  amalgam  as  above  described,  and  then 
cementing  on  the  crown  with  oxy phosphate  in  the  usual 
manner. 

In  a  case  so  inserted,  with  no  antagonizing  teeth,  the  result  is 
the  Fame  as  though  the  inside  of  the  occluding  surface  of  the 
crown  was  filled  with  gold  :  but  if  antagonizing  teeth  are  present, 
the  gold  of  the  crown  is  apt  to  wear  through  in  places  and  expose 
the  amalgam. 


118  ARTIFICIAL  CROWN- AND  BRIDGE-WORK. 

To  Securely  Attach  a  Crown. — If  the  tooth  is  short,  and  the 
occlusion  of  a  character  requiring  the  reduction  of  the  collar 
to  such  a  degree  as  to  suggest  insecurity  when  the  crown  is 
cemented,  a  barbed  or  headed  pin,  which  will  anchor  in  the 
natural  crown  or  root,  should  be  soldered  in  the  center  of  the 
gold  crown,  as  shown  in  Fig.  244.  This  is  done  by  passing  the 
pin  through  a  hole  drilled  in  the  occluding  surface  of  the  crown, 
which  is  then  adjusted  in  the  mouth,  removed,  invested,  and  the 
pin  soldered  from  the  outside.  If  the  pin  is  tapered  and  fitted 
tightly  to  the  hole  (Fig.  245),  the  soldering  can  be  accomplished 
without  investing,  by  holding  the  crown  and  pin  with  solder  in 
position  in  an  alcohol  flame. 

To  Alter  a  Gobi  Grown  to  the  Exact  Form  of  any  Corresponding 
Natural  One. — In  a  case  having  nearly  all  the  natural  teeth 
present,  in  which  the  occluding  surface  and  sides  differ  in  shape 

Fig.  244.  Fig.  245.  Fig.  246. 


from  the  form  of  the  gold  crown,  to  such  an  extent  as  to  inter- 
fere with  its  adjustment,  a  die  of  the  natural  crown  should  be 
made  of  fusible  metal  (Melotte's  Fusible  Alloy, — see  article  on 
"  Molds  and  Dies"),  and  with  it  the  interior  of  the  gold  crown 
should  be  altered  in  shape  sufficiently  to  receive  the  natural 
crown,  by  resting  the  occluding  surface  of  the  gold  crown  on  a 
folded  napkin  and  gently  tapping  the  die  into  it. 

Fig.  246  represents  the  typical  molar  crown  cemented  in 
position. 

The  advantages  of  seamless  contour  crowns  are,  that  they 
represent  perfectly  the  tooth  in  its  anatomical  contour,  present  a 
uniform  surface  of  pure  gold,  which  preserves  its  color  without 
tarnishing,  and  are  quickly  and  easily  adjusted.  Their  defects 
are  inability  to  meet  the  requirements  of  abnormally-shaped 
roots  and  anomalous  articulations. 


CHAPTEE    XL 

GOLD  CROWNS  WITH  PORCELAIN  FRONTS  FOR  TEETH  WITH 
LIVING  PULPS— COLLAR  CROWNS  HYGIENICALLY  CON- 
SIDERED. 

In  the  anterior  teeth,  in  case  of  atrophy  or  erosion,  or  where 
decay  has  destroyed  the  approximal  sides  of  a  tooth  in  such  a 
manner  that  crowning  is  considered  the  most  desirable  operation 
to  perform,  the  pulp  is  frequently  found  unexposed  and  in  a 
normal  condition.  The  importance  of  its  preservation  in  such  a 
case  is  unquestionable. 

The  methods  which  have  been  commonly  used  to  form  a  crown 
under  such  conditions  are  in  many  respects  defective  and 
objectionable,  notwithstanding  the  advantages  their  indorsers 
claim  for  them. 

In  the  first  place,  all  crowns  of  platinum  or  iridio-platinum 
with  body  baked  on  the  labial  aspect  of  the  metal  have  a  dead 
and  unnatural  appearance,  and  from  those  on  which  films  of 
porcelain  representing  teeth  are  baked  the  porcelain  frequently 
chips  off,  and  both  styles  usually  protrude  beyond  the  line  of 
the  adjoining  teeth. 

The  methods  here  presented  are  intended  to  overcome  these 
objections  and  to  produce  more  satisfactory  results.  The  descrip- 
tive details  of  the  crowning  of  a  central  incisor  will  serve  to 
illustrate  one  of  the  methods.  A  model  is  first  made  represent- 
ing the  tooth  in  a  perfect  form.  This  can  be  done  either  by 
shaping  the  natural  tooth  in  the  mouth  with  oxyphosphate  or 
gutta-percha,  taking  an  impression  of  it  in  wax  or  moldine,  and 
forming  a  model  in  plaster  or  fusible  alloy,  or  by  taking  a  natural 
tooth  and  shaping  it  to  correspond,  or,  if  the  operator  is  an 
expert,  carving  one  from  a  piece  of  plaster. 

Two  casts,  one  of  the  coronal  form  of  the  tooth  (Fig.  247), 

11!) 


120 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


and  the  other  of  only  the  palatal  and  approximal  portions  (Fig. 
248),  are  made,  using  the  moldine  in  tubes  with  fusible  metal. 
This  will  consume  only  a  few  minutes.  A  piece  of  gold  and 
platinum  crown  plate,  ISTo.  34  TJ.  S.  standard  gauge,  about  the 
length  and  circumference  of  the  tooth,  is  then  struck  up  on  the 
palato-approximal  cast,  from  which  it  receives  the  palatal  and 
approximal  aspects  of  the  tooth  (Fig.  249).  It  is  then  transferred 
to  the  coronal  cast,  which  is  previously  trimmed  the  thickness 
of  the  gold  plate  upon  the  approximal  surfaces,  and  worked 
down  to  the  exact  form  of  the  tooth  on  the  anterior  portion. 
The  metal,  which  is  then  the  exact  form  of  the  tooth  on  all 
sides,  is  cut  even  at  the  incisive  edge,  the  seam  down  the  front 


Fig.  247. 


Fig.  248. 


Fig.  249. 


Fig.  250.     Fig.  251. 


Fig.  252. 


beveled,  lapped,  and  marked,  then  slightly  opened,  and  the  gold 
slipped  off  the  die.  Guided  by  the  mark,  the  gold  is  then 
pressed  back  to  the  form  assumed  on  the  die,  and  fitted  to  the 
natural  crown,  which  should  have  been  previously  trimmed  and 
shaped  as  described  on  page  35  (Fig.  22),  and  the  joint  on  the 
labial  side  soldered  (Fig.  250).  Into  the  incisive  edge,  which  is 
open,  a  narrow  strip  of  gold,  about  one-sixteenth  of  an  inch  in 
width  and  thick  enough  to  fill  the  space,  is  fitted  and  soldered. 
This  strengthens  the  whole  crown,  and  forms  a  protecting  edge 
for  the  porcelain  front. 

We  have  now  a  gold  contour  crown,  an  exact  imitation  of 
the  tooth  under  treatment.  The  crown  is  then  filled  with 
plaster,  and  the  labial  portion  ground  and  filed  away,  leaving 
the  upper  part  to  form  the  band,  and  the  lower  the  incisive  edge, 
as  represented  in  Fig.  251. 

A  porcelain  tooth  of  the  proper  shade  and  form  is  then  ground 


GOLD  CROWNS  WITH  PORCELAIN  FRONTS.  121 

down — in  which  operation  the  pins  are  obliterated — to  a  thin 
porcelain  front,  thickest  at  the  incisive  edge,  and  fitted  to  the 
space  made  by  cutting  away  the  labial  face  of  the  gold  crown. 
The  porcelain  is  then  removed  and  a  piece  of  platinum  foil 
adapted  to  its  back,  and  turned  just  barely  over  the  edges,  the 
upper  and  lower  of  which  should  be  slightly  tapered  off,  as 
shown  in  Fig.  252. 

The  platinum  can  be  made  to  fit  closely  to  the  porcelain  by 
rubbing  the  edges  on  a  piece  of  cloth  or  chamois,  on  a  flat 
surface.  The  porcelain  front  is  then  adjusted  on  the  crown 
and  cemented  on  one  side  with  wax,  and  the  crown  invested  in 
plaster  and  marble-dust,  so  that  the  seam  along  the  edge  of  the 
platinum  and  gold  is  exposed  on  the  cemented  side  and  at  one 
end  as  shown  in  Fig.  253.  When  the  investment  has  set,  the 
wax  is  removed,  and  small  pieces  of  gold  solder  or  fluxed  gold 
solder  filings,  20-carat  tine,  are  packed  in  and  over  the  seam,  in 

Fig.  253.  Fig.  254.  Fig.  255.  Fig.  256. 


quantity  sufficient  to  make  a  perfect  joint  when  finished.  The 
investment  is  then  heated  uniformly  and  the  seam  soldered. 
Care  must  be  taken  not  to  flow  the  solder  upon  the  porcelain, 
or  to  use  more  borax  than  is  absolutely  necessary,  as  otherwise 
the  porcelain  will  be  fractured. 

When  the  investment  is  cold,  the  crown  is  removed,  again 
invested,  and  the  remainder  of  the  seam  soldered,  or  the  invest- 
ment can  be  immediately  removed  from  the  other  side,  and  the 
soldering  completed;  though  this  latter  plan  is  attended  with 
some  risk  to  the  porcelain. 

After  the  crown  has  gone  through  the  finishing  process,  any 
excess  of  porcelain  on  the  inside  of  the  crown  is  ground  away 
in  a  few  minutes  with  a  small  piece  of  corundum  melted  on  an 
old  oval-shaped  bur.  The  cavity  in  the  crown  is,  meanwhile, 
kept  filled  with  wTater  (Fig.  254). 


122  ARTIFICIAL  CROWX-  AXD  BRIDOE-WORK. 

In  adjusting  the  crown,  the  natural  tooth  can  be  smeared  with 
a  paste  made  of  rouge  and  sweet  oil,  which  will  easily  indicate 
any  point  obstructing  its  perfect  adaptation.  When  fitted,  the 
crown  is  attached  with  oxyphosphate  cement.  Fig.  255  shows 
the  completed  crown. 

In  making  this  style  of  inlaid  crown,  Dr.  J.  B.  Littig  depresses 
the  labial  aspect  of  the  gold  crown  as  much  as  possible,  and  grinds 
and  properly  fits  over  it  a  porcelain  front.  The  porcelain  is 
then  removed  and  a  narrow  strip  of  gold  soldered  around  the 
line  of  the  porcelain  which  will  just  receive  its  edges.  In  this 
setting  of  gold  the  porcelain  is  inlaid  by  cementing  it  with  oxy- 
phosphate and  burnishing  the  edges  of  the  gold  over  on  the 
edge  of  the  porcelain. 

Bicuspids  and  molars  can  be  made  in  either  of  the  methods 
described  by  using  a  contour  crown  of  gold  lined  with  platinum 
(see  chapter  on  Gold  Seamless  Contour  Crowns),  and,  after  its  ad- 
justment, filling  in  the  crown  with  plaster,  and  then  cutting  away 
the  labial  portion  and  replacing  it  with  porcelain  (Fig.  256). 

Facing  or  Enameling  with  Glass  Fitting-Material. — A  gold  crown 
such  as  has  been  above  described  is  made  for  the  case,  or  a  suit- 
able seamless  gold  crown  obtained  or  made.  The  crown  is 
fitted  to  the  tooth  in  the  mouth,  the  sides  properly  stiffened, 
and  the  cusps  or  incisive  edge  strengthened  with  fluxed  solder 
filings,  and  the  crown  boiled  in  acid.  It  is  then  adjusted  in  the 
mouth,  the  portion  of  the  labial  section  which  is  exposed  is  out- 
lined on  the  surface  of  the  gold  with  a  pointed  instrument,  and 
the  crown  is  removed.  The  area  of  the  marked  labial  section 
is  then  ground  quite  thin  with  corundum  wheels  and  points,  and 
with  a  spear-pointed  drill  perforated  in  a  number  of  places 
Fig  257  (see  ^&'  ^57).  The  crown  is  next  adjusted  in  the  mouth, 
and  the  thinned  labial  section  depressed  with  a  burnisher 
inward  or  against  the  natural  crown,  it*  one  is  present, 
for  the  purpose  of  obtaining  space  for  the  inlay,  and 
the  crown  removed.  Some  glass  filling-material  of  the 
proper  shade  is  mixed  with  water  to  the  consistence  of  paste, 
and  with  a  spatula  a  small  portion  of  it  is  spread  over  the 
labial  surface  of  tlfe  gold,  the  surplus  moisture  removed  by 
gentle  pressure  with  a  napkin,  and  dry  particles  of  the  material 


GOLD  CROWNS   WITH  PORCELAIN  FRONTS.  123 

around  the  section  to  be  inlaid  or  enameled  removed  with  a 

dry  camel's-hair  brush.     The  enarneling-material  is  then  fused. 

This  is  best  and  most  easily  performed  in  the  following  manner  : 

A  very  small  muffle  is  made  of  thin  platinum,  in  size  and  form 

similar  to  that  shown  in  Fig.  258.    Thedepres- 

°  .  .  .  Fig.  258. 

sion  in  the  base  is  to  hold  the  crown  in  position, 

and  prevent  its  moving  during  the  baking  of  the 
enamel.  The  seams  of  the  muffle  are  united 
with  the  smallest  possible  quantity  of  pure  gold. 
The  inner  surface  of  the  base  is  given  a  thin 
coating  of  whiting,  the  moisture  evaporated,  and 
the  crown  placed  in  position,  with  the  enamel  part  upward.  The 
sides  of  the  depressed  platinum  can  be  bent  and  altered  to  suit 
different-sized  crowns.  The  whiting  prevents  the  possibility  of 
adhesion  of  the  crown  to  the  platinum  by  the  fusing  of  either 
the  gold  or  enamel.  The  muffle  is  then  placed  on  a  charcoal 
soldering-block,  in  which  an  indentation  has  been  made  to  accom- 
modate the  depressed  base  of  the  muffle,  and  gradually  heated  up 
with  a  gas  blow-pipe,  by  blowing  the  flame  against  the  closed  end 
of  the  muffle  to  a  light  red  heat,  which  will  fuse  the  enamel.  The 
crown  is  then  removed,  sufficient  enamel-material  is  added  to 
give  proper  form  to  the  part,  and  the  fusing  repeated.  The 
surface  of  the  enamel  is  then  ground  level  and  smooth  with  a 
dry  corundum-point,  the  edges  finished  with  sand-paper  disks, 
and  the  dust  removed  with  an  air-syringe.  All  pits  and  inequal- 
ities are  then  filled  in  with  enamel,  and  the  surface  coated  by 
the  aid  of  a  brush  with  some  enamel-material  mixed  quite  thin. 
A  little  is  also  placed  inside  the  crown  at  the  grinding-surface, 
to  clinch  the  inlay  at  that  point.  In  the  last  fusing  the  heat  is 
carried  to  a  higher  point  than  before,  the  open  end  of  the  muffle 
1  icing  turned  toward  the  operator,  so  that  the  degree  of  heat 
received  by  the  crowm  can  be  observed. 

This  method  gives  a  smooth,  dense  inlay  of  enamel.  Any 
particles  that  may  extend  beyond  the  gold  on  the  interior  sur- 
tax of  the  crown  may  be  removed  as  described  under  the  pre- 
vious method. 

Crowning  in  Cases  of  Abrasion. — In  a  case  of  extensive  abrasion 
of  the  incisive  edges   of  the   anterior  teeth,  with   pulp  living 


124  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

though  considerably  calcified  in  the  coronal  section,  crown-work 
to  restore  the  length  and  form  of  the  teeth  is  best  performed  by 
removing  a  portion  of  the  labial  aspect  of  the  natural  crown 
and  then  forming  the  artificial  crown  similar  to  a  gold  collar 
crown  without  the  pin.  An  accurately  adapted  collar,  cemented 
with  oxyphosphate,  will  usually  hold  the  crown  se- 
Fig,  259.  curely.  Fig.  259  gives  an  outline  of  the  construc- 
tion of  such  a  crown.  If  a  case  should  suggest  the 
necessity  of  a  pin,  a  short  one  can  be  so  inserted  as 
not  to  endanger  the  pulp. 

COLLAR  CROWNS  HYGIEN1CALLY  CONSIDERED. 

The  principal  argument  against  ferruled  or  col- 
lared crowns  is  that  they  are  productive  of  irritation 
to  the  peridental  membrane,  ultimately  causing  its 
absorption  and  the  exposure  of  the  collar.  This 
would  be  theoretically  and  practically  true  of  a  rough  or  porous 
substance  encircling  the  root,  or  of  an  imperfectly  and  unskil- 
fully adjusted  or  cemented  ferrule  or  collar  which  would  by  its 
presence  hold  a  position  analogous  to  a  calcareous  deposit,  but 
no  such  comparison  can  be  fairly  made  with  a  perfectly  fitted 
collar,  forming  at  its  edge  a  smooth  and  imperceptible  union 
with  the  sides  of  the  root,  and  presenting  a  uniform  and  benign 
surface  to  the  investing  membrane.  In  case  of  perfectly  adapted 
collars,  when  any  irritation  of  the  membrane  exists,  it  will  be 
found  to  result  from  such  causes  as  usually  produce  it  when 
the  natural  crowns  are  present,  namely,  dental  concretions.  A 
tarnished  and  unclean  condition  of  the  surface  of  the  gold  of 
the  collar  will  produce  irritation  of  the  membranes,  which  is  a 
matter  independent  of  the  collar  itself,  and  easily  remedied  by 
cleansing  and  polishing  the  surface.  Where  an  acid  condition 
of  the  secretions  of  the  mouth  exists,  a  collar  of  platinum  or 
iridium,  or  one  of  gold  and  platinum  crown-metal,  presenting 
the  platinum  surface,  is  suggested  in  preference  to  gold,  as 
these  metals  will  not  be  affected,  but  will  constantly  present  an 
untarnished  surface. 

"When  evidences  of  a  tendency  to  pyorrhea  alveolaris  exist,  a 
collar  adjusted  to  support  bridge-work  should  be  extended  well 


COLLAR  CROWNS  HYGIENICALLY  CONSIDERED.  125 

under  the  gum-margin,  or  the  edge  of  the  collar  kept  consider- 
ably above  it.  Where  pyorrhea  alveolaris  is  present,  a  collar  of 
fine  gold,  properly  fitted  and  extended  to  the  line  of  the  peri- 
cementum, has  often  a  tendency  to  retard  the  disease,  as  calcareous 
deposits  do  not  adhere  to  the  smooth  surface  of  the  gold  so 
readilv  as  to  the  dentine. 


CHAPTER  XII. 


SPECIAL  FORMS  OF  GOLD  CROWNS  WITH  PORCELAIN  FRONTS. 


THE    PARR    CROWN. 

This  crown,  which  in  form  of  construction  possesses  special 
points  of  merit,  is  largely  used  by  Dr.  H.  A.  Parr. 

The  root  is  prepared,  banded,  and  capped  without  a  pin,  the 
same  as  for  a  gold  collar  crown  (A,  Fig.  260).  A  hole  is  made 
in  the  cap,  and  a  post  fitted  in  the  canal.  A  piece  of  gold  plate, 
fully  the  size  of  the  cap  on  the  root,  is  adjusted  on  the  post 
above  the  cap  by  making  a  hole  in  the  gold  in  which  the  post 
will  fit  tightly.    The  gold  plate  is  then  adapted  to  the  cap  on  the 


Fig.  260. 


Fig.  261. 


Fig.  262. 


root,  and  burnished  into  any  open  space  around  the  post, 

forming  an  outside  cap;  the  pin  and  the  outer  cap  are 

then  removed  and  soldered  together  and  adjusted  on 

the  inner  cap,  and  the  edge  of  the  outer  cap  trimmed  even  with 

it  (B).     The  porcelain  tooth  to  form  the  crown,  C,  is  fitted  and 

attached  to  the  outer  cap,  which,  when   finished,  is  cemented 

in  position  as  shown  in  Fig.  261. 

The   advantage   of  this   form  of  crown   is   that   the  root  is 
securely  and  permanently  capped  independently  of  the  crown, 
which  can  be  removed  without  disturbing  the  cap  on  the  root. 
126 


THE  LEECH  CROWN. 


127 


Fig.  263. 


Dr.  Parr,  in  using  this  style  of  crown  in  bridge-work,  constructs 
the  outer  cap  with  a  band  which  half  encircles  the  inner  cap, 
and  tapers  off  from  the  palatal  to  the  labial  section,  as  illustrated 
in  Fig.  262.  The  cap  on  the  root  is  cemented  with  oxyphos- 
phate,  and  the  post  and  outer  cap  with  gutta-percha. 

THE    LEECH    CROWN. 

Dr.  Leech's  crown  is  thus  described  by  Dr.  J.  E.  Dexter:1 
"  A  method  devised  by  Dr.  H.  K.  Leech,  of  Philadelphia, 
shown  in  Fig.  263,  and  described  in  the  Dental  Cosmos  for  April, 
1879,  is  as  follows  :  The  root  is  drilled  out  to  a  depth  of  about 
three-eighths  of  an  inch  in  diameter 
of  about  No.  16,  standard  (American) 
wire  gauge,  the  bottom  of  the  hole 
being  flared  or  enlarged,  and  the 
canal  above  filled  with  gutta-percha. 
A  gold  tube  is  made  to  fit  the  hole 
accurately  and  project  sufficiently  for 
convenience  of  handling,  and  is  sol- 
dered through  a  hole  in  a  gold  base 
struck  to  the  root,  projecting  through 
the  plate  some  distance.  A  plate 
tooth  is  fitted  to  the  root  and  plate  and  soldered  to  the  latter, 
gold  being  flowed  onto  the  plate  and  backing  and  around  the 
projecting  tube  to  form  the  palatal  contour,  and  the  tube  cut  off 
flush  with  the  latter.  We  now  have  a  plate  tooth,  gold  backed, 
with  a  tube-pivot,  the  orifice  of  which  opens  on  the  palatal 
aspect  of  our  tooth.  The  root-end  of  the  tube  is  now  slit  per- 
pendicularly in  three  or  four  places,  for  about  two-thirds  of  it- 
length,  a  thin  sheet  of  warmed  gutta-percha  is  placed  on  the 
base  of  the  crown  around  the  tube,  and  the  whole  is  pushed 
securely  to  place.  Xow  pack  gold  or  tin  into  the  tube,  conch  rising 
the  bottom  portions  so  thai  (k  slit  end  will  spread  and  tightly  fill  thi 
flared  tml  of  th  hoi,  in  tin  root,  and  the  operation  is  complete." 

A  collar  crown  fastened  with  a  tube-pivot  as  described  can  be 
used  to  advantage  in  detachable  bridge-work,  as  the  tube  if 
filled  with  tin  foil  will  admit  of  the  crown  being  easily  detached. 


1  Dental  Cosmos,  May,  1883. 


128  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

THE    LOW    CROWN. 

In  the  method  for  crowning  pulplesa  roots  of  Dr.  J.  E.  Low, 
of  Chicago,  the  root-canal  is  reamed  out  with  an  instrument 
which  at  the  same  time  shapes  the  end  of  the  root,  or  a  portion 
of  it,  to  receive  a  combined  post  and  cap,  which  the  inventor 

Fig.  264. 


calls  a  "  step-plug,"  from  its  peculiar  form.  There  are  seven 
sizes  of  the  cutting  instruments  (Fig.  264),  and  corresponding 
exactly  with  them  seven  sizes  of  the  step-plugs.  These  step- 
plugs  are  not  unlike  a  minute  cone-pulley  set  in  a  saucer-shaped 
cap  upon  the  bottom  of  which  is  a  stout  boss.  They  are  made 
of  platinum  and  nickel.     As  these  last  fit   the  prepared   root 

accurately,  it  is   claimed   that   they 
Fig.  265.  Fig.  266.      Fig.  267.  afforc)    a   secure  foundation  for   the 

4  artificial  crown  and  also  prevent 
longitudinal  fracture  of  the  root. 
To  describe  and  illustrate  the  pro- 
cess, the  root  of  a  central  incisor  (Fig. 
265)  is  selected.  The  end  of  the 
root  is  first  ground  level  with  the  palatal  margin  of  the  gum.  A 
cutting  instrument  of  suitable  size  is  then  selected,  with  which 
the  root  is  shaped  as  shown  in  Fig.  266.  The  end  of  the  root  is 
removed  enough  to  permit  the  palatal  edge  of  the  cap  of  the  step- 
plug  (Fig.  267),  which  is  then  adjusted,  to  pass  just  below  the 


THE  LOW  CROWN. 


129 


margin  of  the  gum.  Fig.  268  shows  the  step-plug  in  position, 
and  ready  for  the  adjustment  of  the  porcelain  front  (Fig.  269)  and 
the  construction  of  the  crown,  which  is  completed  as  in  methods 
previously  described.  The  porcelain  front  when  adapted  should 
meet  the  labial  margin  of  the  gum,  the  labial  surface  of  the  end 
of  the  root  being  trimmed  (with  the  cap  in  position)  with  a 
corundum-wheel  when  necessary  to  permit  it.  When  the 
porcelain  front  is  to  be  adjusted  in  the  mouth,  the  backing 
should  be  warmed,  a  small  quantity  of  resin  and  wax  cemented 
upon  it,  the  tooth  placed  in  position  in  the  mouth,  and  the  con- 
vex surface  of  the  step-plug  cap  carefully  imbedded  in  the  wax. 
The  wax  and  the  porcelain  front  should  next  be  carefully  removed 


Fig.  268. 


Fig    270. 


Fig    273. 


Fig.  27o. 


Fig.  269. 


Fig.  272. 


Fig.  274. 


Fig.  276. 


and  then  the  step-plug,  using  pliers  for  the  last.  The  step-plug 
is  then  placed  in  the  wax  impression,  to  which  it  is  fixed  with  a 
heated  spatula,  and  invested  for  soldering.  Fig.  270  shows  the 
completed  crown  ready  for  final  adjustment,  and  Fig.  271  gives 
a  sectional  view  of  it  in  position. 

In  crowning  bicuspid  roots,  one  step-plug  in  the  palatal  side  of 
the  root  (Fig.  272)  is  usually  sufficient,  the  remaining  exposed 
surface  of  the  root-end  being  covered  by  adapting  thin  platinum 
plate  over  it  and  onto  the  surface  of  the  cap  before  adjusting 
the  porcelain  front  (Figs.  273  and  274).  Figs.  275  and  276  show 
the  completed  bicuspid  crown  before  and  after  the  final  adjust- 
ment.    Molar  roots  are  capped  similarly,  using  two  step-plugs. 

The  plugs  are  useful  in  building  up  badly  decayed  roots  to 
support  and  retain  all-gold  crowns. 

10 


130 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  277. 


THE   PERRY    CROWN. 

Dr.  Safford  G.  Perry,  of  New  York,  employs  a  porcelain 
crown  in  combination  with  a  capped  root.  A  bicuspid  will  be 
taken  as  a  typical  case  to  illustrate  Dr.  Perry's  method.  The 
end  of  the  root,  by  trimming  the  edge,  is  given  the  tapering 
form  shown  at  A,  Fig.  277.  The  collar  (B) 
is  made  very  narrow.  A  cap  is  fitted  on 
the  collar,  and  a  post  or  posts  fitted  in  the 
roots  and  through  the  cap.  The  entire 
cap  is  made  of  platinum  soldered  with 
pure  gold.  Enough  of  the  post  is  allowed 
to  extend  beyond  the  cap  to  attach  and 
firmly  retain  the  porcelain  crown  (C). 
One  or  two  holes  to  serve  as  vents  are 
drilled  through  the  top  of  the  cap,  and  it  is  set  in  place  with 
oxyphosphate,  the  excess  escaping  through  the  holes.  The  holes 
are  then  reamed  out  and  filled  with  gold,  and  the  edge  of  the 
collar,  under  the  gum,  is  burnished  to  the  root.  The  porcelain 
crown  used  is  similar  in  principle  to  the  Ilowland  crown,  but 
differs  in  the  details  of  its  formation.  The  base  is  given  a  curve 
approximating  that  of  the  line  of  the  margin  of  the  gum,  with 
the  palatal  portion  projecting  slightly  above  it,  to  include  a  little 

of  the  cervix.  The  cavity  in  the 
porcelain  is  given  a  size,  form, 
and  position  which  will  receive 
the  posts  extending  from  the  cap 
without  impairing  the  strength 
of  the  crown-walls.  Thus  the}7 
/0\     \T^  I      1       I     are   made   round  in   the  incisors 

LJ  \y  ^  ^"^  and  cuspids  (A,  Fig.  278),  oval  in 
the  bicuspids  (A,  Fig.  279),  and  following  the  curve  of  the  line 
of  the  posts  in  the  molars.1 

1  The  form  of  porcelain  crown  described  is  also  used  by  Dr.  Perry  without 
capping  the  root,  similarly  to  the  Howland  crown.  In  such  cases  he  usually 
protects  the  end  of  the  root  either  with  a  surface  of  condensed  gold  foil  anchored 
in  a  reamed  cavity  formed  around  the  post  in  the  root-canal,  or  with  a  very  thin 
disk  of  gutta-percha.  The  disk  with  the  aid  of  heat  or  chloroform  is  made  to 
form  a  line  of  union  between  the  root  and  crown.  In  both  methods  oxyphos- 
phate is  used  in  the  cavity  which  receives  the  post  to  attach  the  crown. 


Fig.  278. 


Fig   279 


A 


THE  PERRY  CROWB  131 

A  suitable  crown  (C,  Fig.  277)  having  been  selected,  it  is  ground 
and  fitted  in  proper  position  on  the  cap.  This  operation  is  facili- 
tated by  perforating  a  disk  of  marking-paper  with  th<  |  3te  and 
adjusting  it  on  the  cap.  Then,  as  the  crown  is  placed  on  the 
and  pressed  against  it,  points  which  prevent  perfect  adjustment 
are  marked  on  the  porcelain.  By  this  means  a  el  -  int  is 
easily  secured.  The  edge  of  the  porcelain  should  be  fitted  under 
the  free  margin  of  the  gum.  especially  at  the  cervico-palatal 
part.  The  porcelain  crown  is  next  set  over  the  pro/-.  I  _  ins. 
and  cemented  to  the  cap  with  oxyphosphate. 

The  advantage  of  this  method  is.  that  the  root  being  slightly 
tapered,  the  collar  can  be  made  to  fit  absolutely,  while  the 
excess  of  oxyphosphate  is  gotten  rid  of  through  the  vent-holes, 
instead  of  being  squeezed  out  around  the  edge  of  the  collar. 
The  edge  of  the  collar  being  made  to  a  knife-edge,  can  be 
properly  burnished  before  the  crown  is  placed,  so  that  it  will  n  't 
irritate  the  gum  or  make  a  shelf.  The  crown  covt-rs  the  cap. 
and  can  usually  be  ground  and  fitted  bo  a-  to  entirely  hide  any 
exposed  portion  of  the  collar,  the  junction  of  which  with  the  cap 
should  be  trimmed  and  then  rounded  with  a  burnisher,  to  give  a 
form  which  will  better  meet  the  inter!  the  porcelain  cap  or 

crown.  Fig.  279  shows  the  finished  crown.  Fig.  278  gives  a 
sectional  view  of  a  central  incisor.  The  porcelain  can  be 
replaced  at  any  time  in      a  fracture  without  disturbing  the 

cap  on  the  root.     The  easy  repair  thus  afforded,  the  simplicity 
of  construction,  and  the  artistic  result,  are  the  special  features 
this  form  of  crown. 


CHAPTER  XIII. 

CROWNING  FRACTURED  TEETH  AND  ROOTS— CROWNING 
MOLAR  ROOTS  DECAYED  APART  AT  BIFURCATION— CROWN- 
ING IN  CASES  OF  IRREGULARITY. 

The  crowning  of  fractured  teeth  and  roots  is  a  process  that 
requires  skill  and  delicate  treatment.  Its  practicability  depends 
on  the  nature  of  the  fracture,  the  previous  health  of  the  parts, 
and  the  length  of  time  that  has  elapsed  since  the  occurrence 
of  the  injury. 

LONGITUDINAL   FRACTURE    OF    THE    CROWN    AND   ROOT. 

By  this  is  meant  a  fracture  extending  lengthwise  through 
the  crown  or  what  remains  of  it,  and  down  the  root  or  roots. 
Foreign  substances  having  been  removed  from  within  and  around 
the  parts,  the  crevice  of  the  fracture  is  syringed  thoroughly 
with  a  solution  of  carbolic  acid  and  tepid  water.  The  fractured 
parts  of  the  root  are  then  drawn  together  with  waxed  floss 
silk,  passed  at  least  twice  around  the  tooth,  and  tied,  the 

S^i  ends  being  passed  through  twice  in  forming  the  knot. 
J  The  pulp-chamber  is  then  prepared,  and  dovetail  slots 
drilled  across  the  parts  (Fig.  280).  If  it  is  suspected  that 
in  the  preparation  any  particles  of  dentine  have  invaded  the 
crevice  of  the  fracture,  the  ligature  must  be  removed,  the  parts 
again  syringed,  and  the  ligature  readjusted.  Aromatic  sulphuric 
acid  followed  by  water  can  be  recommended  for  the  final  injec- 
tions. The  upper  parts  of  the  root-canals  are  then  filled  with 
gutta-percha,  and  the  main  body  of  the  cavity  and  the  slots  with 
a  hard,  quick-setting  amalgam.  A  collar  crown  should  always  be 
used  in  these  cases.  If  the  form  to  be  used  has  a  post,  a  short, 
small  tube  of  gold  or  platinum  should  be  set  in  the  amalgam  in 
proper  position  to  receive  it.  At  the  next  visit  of  the  patient 
132 


CROWNING  FRACTURED  TEETH  AND  ROOTS.  133 

the  ligature  is  removed  and  the  parts  carefully  prepared  for 
crowning.  The  circumference  of  the  root  is  first  measured  with 
a  wire,  a  tight-fitting  collar  constructed,  and  the  crown  then 
completed  in  the  usual  manner.  The  crown  may  be  favored  by 
leaving  a  slight  space  between  its  occluding  surface  and  the 
antagonizing  tooth. 

The  great  drawback  in  these  cases  is  that  the  patient  generally 
fails  to  present  himself  immediately  for  treatment,  and  foreign 
substances  work  into  the  fracture,  causing  inflammation,  which 
is  difficult  to  control.  Often  subsequent  to  treatment  a  septic 
condition  of  the  fracture  supervenes,  the  irritation  caused  thereby 
and  the  exudations  from  the  fracture  becoming  so  annoying  that 
extraction  is  the  only  alternative. 

Teeth  fractured  as  above  described  are  rarely  found  with  living 
pulps. 

FRACTURE  OF  THE  CROWN  WITH  SLANTING  FRACTURE  OF 

THE  ROOT. 

Fractures  of  this  kind  are  common,  especially  in  bicuspids, 
where  large  fillings  are  inserted  extending  from  the  anterior  to 
the  posterior  approximal  walls,  leaving  the  separated  buccal  and 
palatal  cusps  to  bear  the  brunt  of  mastication. 

In  such  cases  the  fracture  seldom  extends  beyond  the  edge  of 
the  alveolar  process.     The  fractured  part  having  been  carefully 

Fig.  281.  Fig   282. 


removed,  a  dovetail  slot  is  made  in  the  crown  or  root,  into 
which  gutta-percha  is  inserted  for  a  day  and  the  membrane  of 
the  gum  pressed  back,  so  as  to  fully  expose  the  surface  of  the 
fracture.  The  form  of  the  root  is  then  in  a  measure  restored 
with  amalgam,  which,  when  hard,  is  polished  |  Figs.  281  and 
282  . 


134  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

The  root  is  then  crowned,  the  mode  of  operation  being  the 
same  as  in  any  other  case. 

PERFORATION    OF    A   SIDE-WALL    OF   A    ROOT-CANAL    OR    OF 
THE    DENTINE   AT    THE    BIFURCATION    OF   THE    ROOTS. 

Extensive  perforation  by  decay  in  these  locations  below  the 
line  of  the  edge  of  the  alveolar  process  seldom  admits  of  suc- 
cessful treatment.  AVhen  the  decay  is  of  limited  extent,  and 
a  very  slight  perforation  has  been  produced  by  its  thorough 
removal  or  by  the  improper  or  careless  use  of  a  bur,  cicatricial 
tissue  may  be  induced  to  form  over  the  part  by  creating  and 
maintaining  a  sterilized  condition,  and  then  sealing  the  cavity. 

The  method  of  procedure  is  as  follows:  Inject  the  canals  with 
peroxide  of  hydrogen,  then  bathe  with  alcohol,  dry  with  hot  air, 
and  fill  the  canals  closely,  but  not  tightly,  with  cotton  saturated 
with  oil  of  cloves,  and  seal  the  cavity  with  gutta-percha.  Renew 
the  dressing  at  intervals,  preventing  the  entrance  of  saliva  until 
the  exudation  of  serum  ceases  at  the  perforation  and  a  film  of 
cicatricial  tissue  has  been  formed.  Dry  the  canal  thoroughly,  and 
fit  closely  over  the  perforation  a  small,  flat  piece  of  gutta-percha, 
warmed  and  applied  with  a  gentle  pressure,  sufficient  only  to 
produce  adhesion  without  forcing  the  gutta-percha  through. 
Previously  painting  the  adjacent  walls  with  thin  chloro-gutta- 
percha  will  cause  the  gutta-percha  to  adhere  readily.  The  tilling 
of  the  canal  can  then  be  carefully  completed.  If  this  method 
proves  unsuccessful  and  inflammation  ensues,  the  position  of  the 
perforation  should  be  carefully  calculated,  and  an  artificial  fistula 
should  be  formed  on  a  direct  line  with  it 

"Pin    9ft^ 

through  the  gum  and  alveolar  process  (see 
Fig.  283).  Carbolic  acid  may  be  used  as  de- 
scribed at  page  29,  to  obtund  the  tissue.  The 
necessary  perforation  through  the  alveolar 
process  should  be  small  in  diameter,  and 
should  be  made  with  a  drill.  Injections 
should  be  made  through  the  fistula,  and  the 

perforation  sealed  with  gutta-percha  similarly  to  the  closing  of 

a  foramen  in  cases  of  alveolar  abscess. 


CR0WN1XG  MOLAR  ROOTS. 


135 


CROWNING    MOLAR     ROOTS    DECAYED    APART    AT    THE 
BIFURCATION. 


Fig.  284. 


The  roots  of  a  molar  decayed  apart 
at  the  bifurcation  can  often  be  crowned 
servieeably  by  making  a  cap  for  each 
root  separately,  and  then  soldering  the 
sides  of  the  cap  together  (Fig.  284). 
Where  one  root  is  missing,  the  other 
can  be  crowned  singly. 


DR.    FARRAR'S    CANTILEVER    CROWN. 

Figs.  285  and  286  represent  Dr.  J.  X.  Farrar's  cantilever 
crowns.  He  describes  them  as  follows:  Fig.  285  illustrates  a 
sectional  view  of  three  teeth,  and  an  amputated  first  bicuspid 
root  preserved  by  a  screw,  showing  the  application  of  the  canti- 
lever  crown  T  P,  set  upon  the  decayed  second  bicuspid  and 


Fig.  285. 


Fig.  286. 


made  to  project  over  to  bridge  the  space  formed  by  the  loss  of 
the  first  bicuspid,  and  resting  in  contact  with  the  cuspid  so  as  to 
connect  the  broken  line  of  masticating  surfaces  and  prevent 
tilting  forward  of  the  second  bicuspid.  The  abscessed  root  here 
shown  was  extracted.1  Fig.  286  illustrates  tin-  appearance  of  two 
molars,  the  posterior  half  of  one  of  which  is  destroyed,  showing 
also  the  application  of  two  thimble-crowns,  which  are  con- 
structed so  as  to  form  a  cantilever  bridge  over  the  chasm  by 
locking  midway  in  such  a  manner  as  to  prevent  tilting  or  sliding 
of  surfaces,  and  at  the  same  time  be  easily  cleansed  by  a  quill 
or  thread. 


1  Dental  Cosmos,  vol.  xxvi,  No.  3. 


136 


ARTIFICIAL   CROWN-  AND  BRIDGE-WORK. 


METHODS  OF  CROWNING   IN    CASES   OF   IRREGULARITY. 

Fig.  287.  Fig.  287  shows  a  method  of  treat- 

ing  a  case  of  irregularity  without  de- 
stroying the  vitality  of  the  pulp.  The 
tooth  at  B,  which  stood  inside  the  line 
of  the  lower  teeth  when  the  mouth 
was  closed,  was  trimmed,  shaped,  and 
capped.  To  this  cap  was  attached 
the  tooth  at  A,  with  an  oval-shaped 
piece  of  gold  that  cleared  the  lower 
teeth  in  occlusion.  The  cap  was  then 
cemented  to  the  natural  crown. 
Fig.  288  represents  a  case  of  irregularity  treated  by  Dr.  Bon- 
will,  who  says  in  his  description  of  it, — 

"  This  shows  a  case  of  irregularity  which  was  beyond  correc- 
tion, on  account  of  the  poor  character  of  the  teeth,  their  position 
in  the  palatal  arch,  and  the  age  of  the  patient.     In  such  cases  I 

Fig.  288. 


do  not  hesitate  to  cut  off  the  crown,  destroy  the  pulp,  and  insert 
an  artificial  crown.  The  crown  is  brought  in  the  circle  and  con- 
nected with  the  root  by  a  strip  of  heavy  gold  plate.  The  plate 
is  attached  to  the  root  with  a  post  or  a  screw  with  a  nut." 


CHAPTEK    XIV. 

PARTIAL   CROWNS. 

Gold. — Partial  crowns  of  gold  for  the  protection  of  plastic 
filling's  in  large  cavities  and  for  the  restoration  of  contour  are 
often  desirable  when,  for  any  reason,  a  solid  metallic  filling  cannot 
well  be  inserted.  The  cavity  having  been  properly  excavated, 
its  orifice  is  trimmed  as  uniformly  straight  or  circular  as  its 
position  and  character  will  allow,  and  the  edge  of  the  enamel 
beveled  off,  tapering  toward  the  center.  In  the  preparation  ot 
cavities  in  the  grinding-surface,  trimming  and  cutting  away  the 
enamel  should  be  confined  to  that  surface.  In  approximal 
cavities  which  reach  the  grinding-surface,  it  is  advisable  to 
extend  them  in  that  surface  and  bring  the  gold  over 
and  anchor  it  there,  so  as  to  afford  greater  security  Fl°-  289- 
against  its  displacement  in  mastication.  Where  de- 
cay extends  close  to  the  margin  of  the  gum,  if  the 
tooth  is  trimmed  away  so  that  the  gold  will  extend  just 
under  its  free  edge,  a  recurrence  of  decay  at  that 
point  will  be  avoided.  The  bicuspi<J  shown  in  Fig.  289  will 
serve  as  a  typical  case  to  illustrate  the  constructive  details. 

The  cavity  having  been  properly  prepared,  a  die  of  the  tooth 
in  its  original  form  is  then  secured.  For  this  purpose  the  mold 
is  made  by  taking  an  impression  of  the  tooth  with  wax,  making 
a  plaster  model,  and  then  restoring  the  contour  and  forming 
from  it  the  mold  in  gutta-percha  or  moldine;  or  the  shape  of  the 
natural  tooth  may  be  restored  with  wax  or  gutta-percha  and  the 
mold  made  directly  from  it  in  plaster.  The  die  and  counter- 
die  having  been  formed  (see  article  on  "Molds  and  Dies"),  a 
piece  of  pure  gold,  No.  28  to  30  standard  gauge,  the  exact  thick- 
ness being  governed  by  the  size  and  nature  of  the  cavity,  is  struck 
up  to  the  form  and  size  of  the  part  to  be  capped.     The  gold  is 

137 


138 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  291. 


then  adjusted  to  the  cavity,  to  the  margin  of  which  the  edges 
are  trimmed  and  burnished  to  fit  close  and  flush.  In  the  case 
of  large  cavities  including  apart  or  the  whole  of  the  approximal 
surface,  a  model  of  the  tooth  and  the  empty  cavity  from  an  im- 
pression taken  in  wax  will  sometimes  facilitate  and  guide  the  pre- 
liminary trimming  and  shaping  of  the  gold.  Two  headed  pins 
fixed  on  the  inside  of  the  cap  (Fig.  290)  are  usually  sufficient 
to  secure  it,  but  others  can  be  added  if  the  con- 
Fig.  290.  ditions  of  the  case  seem  to  require  it.  In  com- 
pound cavities,  including  one  side  and  the  grind- 
ing-surface,  one  pin  at  least  should  be  fixed  in  the 
latter  portion.  Where  the  grinding  and  both 
approximal  surfaces  are  included,  a  wire  should 
be  extended  from  one  side  to  the  other  (Fig.  291), 
but  the  brace  should  not  touch  the  bottom  of  the 
cavity. 

In  pulpless  teeth  the  pin  from  the  upper  part  of 
the  cap  should  extend  up  the  canal,  giving  great 
stability  in  such  cases  (Fig.  292). 

In  soldering  the  pins  or  loops  when  inserted  in 
holes  drilled  in  the  gold,  a  little  solder  can  be  flowed 
over  the  adjacent  parts  if  deemed  necessary  to 
stiffen  and  strengthen  them. 

Oxyphosphate  is,  as  a  rule,  the  best  to  be  used 
in  connection  with  these  caps,  as  it  forms  a  solid 
and  unyielding  foundation,  and,  when  properly 
protected  from  the  fluids  of  the  mouth  by  a  care- 
fully adjusted  cap,  is  very  durable. 

The  cement  should  befirst  inserted  in  the  cavity, 
and  then  a  small  quantity  placed  around  the  pins 
of  the  cap,  which  should  be  immediately  adjusted  accurately 
in  position.  When  gutta-percha  is  used,  it  is  heated  and  applied 
in  the  same  manner  to  cavity  and  cap.  The  cap  is  then  heated, 
pressed  into  position,  and  held  there  until  the  gutta-percha 
hardens.  This  can  be  hastened  by  the  application  of  cold 
water  from  a  syringe.  The  surplus  of  gutta-percha  is  then 
removed,  and  the  edges  of  the  gold  burnished. 

These  caps  applied  to  teeth  with  living  pulps  show  durability 


Fig.  292. 


PARTIAL  CROWNS.  13!) 

of  a  commendable  character.  The  advantage  they  possess  over 
pieces  of  porcelain  is  found  in  the  close  joint  that  can  be  made 
with  the  edge  of  the  enamel  by  burnishing  the  gold  against  it. 

Dr.  H.  A.  Parr,  in  this  style  of  work,  adapts  No.  60  platinum 
foil  to  the  form  of  the  inner  walls  of  the  cavity  and  just  over  its 
edges  by  the  aid  of  burnishers  and  cotton  twisted  on  the  end  of 
an  instrument,  assisted  by  frequent  annealing  of  the  platinum. 
The  matrix  thus  formed  is  then  filled  with  wax,  chilled,  and 
removed  from  the  cavity  and  invested,  after  which  fine  gold  or 
22-carat  solder  is  melted  into  it.  The  removal  of  the  matrix 
from  the  cavity  can  be  facilitated  by  the  insertion  in  the  wax  of 
a  pin  or  a  short  piece  of  wax,  which  is  grasped  with  tweezers. 
The  plug  of  gold  thus  formed  is  properly  trimmed  and  polished,, 
and  cemented  in  the  cavity  of  the  tooth.  When  completed,  it 
has  the  appearance  of  a  gold  filling.  If  necessary,  the  cavity 
can  be  previously  partly  filled  with  amalgam  or  shaped  with  it, 
to  give  a  better  form  to  permit  the  removal  of  the  shell  of  plat- 
inum foil.  Plugs  so  made  can  occasionally  be  utilized  as  an 
anchorage  for  bridge-work. 

Dr.W.  B.  Ames,  of  Chicago,  makes  solid  gold  tips  for  abraded 

pulpless  teeth  in  the  following  manner  for  cases  in  which  he 

prefers  not  to  insert  fillings  :  An  opening  is  made  through  the 

occluding   surface  of  the    crown   into  the   root-canal.     A  flat 

po.-t,  wide  enough  to  fit  closely  in  the  pulp-chamber  across  its 

greatest  diameter,  thus  tending  to  prevent  any  rotary  motion  of 

the    £>;old   tip,    is   then    formed.     A  very  thin 

.  Fig  293. 

piece  of  pure  gold  plate,  say  Xo.  35  American 

gauge,  is  adapted  and  burnished,  with  hand- 
burnishers  and  Herbst's  revolving  agate  points, 
into  all  the  irregularities  of  the  abraded  sur- 
face, and  into  the  orifice  of  the  pulp-chamber. 
The  gold  is  then  trimmed  flush  and  even  to  the 
edges,  and  burnished  just  over  them.  An  opening  is  next  made 
in  the  gold  cap,  and  through  it  the  post  is  inserted  in  position. 
A  strip  of  thin  gold  plate  or  platinum  foil  is  next  adapted  around 
the  tooth,  wrell  over  and  above  the  edge  of  the  gold  eap,  and 
trimmed  to  the  length  desired  for  the  tip.  With  the  gold  cap 
and  post  placed  accurately  in  position,  the  cavity  formed  by  the 


140 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fio.  294. 


strip  of  plate  or  foil  encircling  the  tooth  is  filled  with  wax  cement, 
and  cap,  post,  and  plate  or  foil  removed  and  invested  to  the 
lower  edge  of  the  latter  (see  Fig.  293).  The  investment  is  then 
heated,  and  20-earat  gold  plate  or  20-  or  22-carat  solder  melted 
into  the  matrix  formed  by  the  plate  or  foil  over  the  cap.  The 
surplus  gold  is  then  trimmed  to  the  edge  of  the  abraded  surface 
of  the  tooth  and  to  the  desired  form  for  the  tip.  When  finished, 
the  gold  tip  is  cemented  in  position  with  a  thin  mixture  of  oxy- 
phosphate.  Fig.  294  gives  a  sectional  view  of  a  central 
incisor  tipped  in  this  manner.  In  cases  of  living  pulps, 
two  or  three  small  pins,  as  the  ease  may  suggest,  are 
used  in  holes  doubled  on  each  side  of  the  pulp,  in  the 
manner  shown  in  Figs.  300  and  301.  If  the  gold  tip 
required  is  short,  the  ends  of  the  pins  extending  above 
the  cap  will  hold  and  maintain  enough  solder  in  posi- 
tion to  give  material  for  proper  contouring,  without 
enveloping  it  with  a  matrix  of  platinum  or  gold  foil  as 
previously  described. 

Porcelain  and  Gold. — The  partial  restoration  with  porcelain  and 
gold  of  an  incisor  crown  such  as  is  shown  in  Fig.  295  is  often  desir- 
able. The  edges  of  the  crown  to  form  the  joining  with  the  porce- 
lain are  trimmed  straight  and  level,  and  then  polished.  A  shallow 
groove  is  generally  formed  to  advantage  at  A,  Fig.  296.     A  very 


Fig.  296. 


Fio.  297. 


C-' 


6 


thin  piece  of  platinum  is  then  adapted  to  the  crown  as  shown  atB, 
Fig.  297.  The  pin  C  is  fitted  to  the  root-canal,  passing  through 
the  platinum.  The  post  and  cap  of  platinum  are  then  attached 
with  wax,  removed,  invested,  and  soldered  with  pure  gold.  A 
little  of  the  gold  at  the  same  time  is  flowed  over  the  cap.  The 
cap  and  post  are  then  adjusted  to  the  crown,  and  the  cap  is 


PARTIAL  CROWNS. 


141 


trimmed  level  and  burnished  closely  against  the  surface  of  the 
portion  to  be  restored  and  into  the  groove  at  A,  Fig.  296.  At 
this  stage  of  the  work,  to  facilitate  the  subsequent  operations,  an 
impression  can  be  taken  which  will  remove  in  it  the  cap,  and  from 
this  a  model  can  be  made.  A  cross-pin  porcelain  tooth  is  then 
ground  down  to  a  size  and  shape  that  will  properly  restore 
the  part  and  form  an  accurate  joint  with  the  labial  edge  of 
the  natural  crown.  The  porcelain  is  then  backed,  cemented  to 
the  cap,  removed,  and  soldered  with  20-carat  solder.  The  partial 
crown  when  properly  finished  is  cemented  in  position  with 
oxyphosphate. 

In  a  case  such  as  is  represented  in  Fig.  298  the  cap  is  shaped 
to  the  surface  of  the  dentine  and  enamel  at  A  and  over  its  palatal 
edge,  and  the  backing  on  the  porcelain  is  extended  out  over 
the  palatal  edge  of  the  enamel  at  B.  The  two  sections  of  the 
platinum  are  united  in  the  soldering. 


Fig.  298. 


Fig.  299. 


Fig.  300. 


Fig.  299  illustrates  a  fractured  central  incisor  in  which  the 
pulp  was  not  exposed,  restored  with  porcelain  by  Dr.  J.  Bond 
Littig,  of  New  York.  The  cap  to  the  fractured  part  was 
fastened  by  three  small  pins  as  shown  in  Fig.  300,  which  illus- 
trates the  details  of  the  construction. 

"  Where  the  piece  broken  off  is  so  narrow  that  the  porcelain 
tooth  cannot  be  ground  to  fit  in  the  ordinary  way,  without  cut- 
ting out  the  pins,"  Dr.  Littig  describes  his  method  as  follow- : 
"First  cut  a  groove  in  the  end  of  the  broken  tooth,  making- 
slight  undercuts.  The  pins  of  a  suitable  porcelain  tooth  are  bent 
outward,  and  the  ends  flattened.     The  porcelain  is  then  ground 


142 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


away  from  both  ends,  until  it  is  made  as  narrow  as  the  natural 
tooth  is  thick  or  nearly  so.  The  piece  is  fitted  to  the  end  of  the 
tooth  by  placing  the  pins  in  the  groove.*  If  the  joint  is  not  good, 
grind  away  from  either  tooth  or  porcelain  until  it  is  perfect. 
Then  set  the  piece  with  zinc  phosphate,  and  after  it  has  become 
hard,  grind  the  tip  to  shape  in  the  mouth,  and  polish  with  moose- 
hide  disk  and  pumice-stone.     Fig.  301  illustrates  the  second 


Fig.  301. 


Fig.  302 


method  ;  the  ground  porcelain  tip,  prepared  crown,  and  restored 
tooth  being  shown  separately."  Dr.  Littig's  third  method  is  to 
first  cap  the  fractured  part  with  platinum,  allowing  the  ends  of 
the  pins,  which  are  soldered  with  pure  gold,  to  project  below  the 
cap.  English  porcelain  body  the  desired  form  for  the  tip  is  then 
baked  on  the  cap.  The  porcelain  by  this  method  is  secured  to  the 
platinum  forming  the  cap,  by  the  platinum  pins  embodied  in  it. 
Figs.  302,  303,  and  304  show  how  Dr.  W.  F.  Litch's  pin-and- 
plate  process  may  be  utilized  for  the  attachment  of  porcelain 
tips  for  broken  or  decayed  incisors,  when  the  appearance  of 
gold  fillings  is  obnoxious  to  the  patient.     A  represents  the  por- 


Fig.  304. 


Fio.  305. 


Fig.  306. 


celain  tips;  13,  the  space  to  be  filled  by  them;  C  and  D,  the  open- 
ings for  retaining-pins;  F  and  G,  openings  in  the  base-plates  (E) 
for  the  pins.  Fig.  304  shows  the  appliance  with  pins  attached. 
Figs.  305  and  306  illustrate  a  case  in  which  the  contour  of  a 


PARTIAL  CROWNS. 


143 


Fig.  307. 


single  incisor  tooth  was  restored  in  this  manner.  Fig.  305  shows 
the  palatal  aspect  of  the  tooth,  in  which  the  openings  for  two 
retaining-pins  were  drilled,  the  openings  being  made  quite  small. 
In  Fig.  306  is  seen  the  porcelain  tip  attached  to  the  plate  and 
ready  for  mounting.  The  two  retaining-pins  will  be  observed 
soldered  to  the  plate.  In  this  case  the  cervical  margin  of  the 
natural  tooth  was  made  level  to  afford  a  secure  resting-place  for 
the  porcelain  tip. 

Dr.  C.  H.  Land,  of  Detroit,  employs  porcelain  partial  crown- 
work  in  cases  of  the  character  here  described.  He  first  forms 
a  dovetail  cavity  in  the  central  portion  of  the  section  to  be 
tipped  or  contoured,  and  then  adapts,  aided  by  frequent  annealing, 
a  piece  of  platinum  foil  (Xo.  60 
U.  S.  gauge)  to  the  cavity  and 
surface  of  the  part,  by  means 
of  burnishers,  and  a  pellet  of 
cotton  twisted  on  the  end  of  an 
instrument.  The  platinum  is 
then  removed,  and  on  its  sur- 
face porcelain  body  is  placed, 
and  baked  in  the  muffle  of  a 
furnace.  (Dr.  Land's  Midget 
Furnace,  Fig.  307,  is  the  most 
suitable  for  the  purpose,  as  each 
baking  of  the  porcelain  can  be 
performed  in  about  ten  min- 
utes.) After  the  first  baking,  the 
thin  platinum,  which  is  usually 
warped  by  the  shrinkage  of  the 
porcelain  body  in  the  baking, 
is  corrected  by  readjustment  to 
the  tooth,  in  doing  which  the 
porcelain  is  usually  fractured. 
The  interstices  and  fractures  in 
the  porcelain  are  then  filled,  the  part  properly  shaped  with  body, 
and  the  porcelain  rebaked,  and  again  adjusted  and  fitted  in 
position.  The  platinum  is  next  trimmed  free  of  the  edge  with 
a  corundum-wheel,  and  the  porcelain  shaped  accurately  to  the 


144 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


form  desired.     Any  imperfections  existing  are  again  filled  with 
body,  and  the  final  baking  given. 

Dr.  Land  claims  that  in  such  cases  porcelain,  if  fitted  to  the 
irregularities  of  the  cavity,  will  be  securely  retained  when 
cemented  with  oxyphosphate.  An  additional  attachment  is 
obtained  by  placing  a  piece  of  iridio-platinum  wire  across  the 
retaining  cavity  of  the  tooth,  with  the  ends  caught  or  bent 
against  the  sides,  and  then  forming  a  dovetailed  groove  across 
the  base  of  the  porcelain  tip,  which  will  receive  the  wire.  When 
a  porcelain  tip  is  desired  without  the  platinum  base,  after  the 
final  baking,  the  platinum  is  removed  by  tearing  it  off  the  por- 
celain. "When  this  is  the  intention,  the  platinum  should  not  pre- 
viously be  trimmed  close,  but  should  be  left  extending  around 

Fiq    30*. 


and  slightly  beyond  the  edge  of  the  porcelain.  Fig.  308  illus- 
trates a  case  of  atrophy,1  in  which  the  tips  of  the  central  incisors 
were  contoured  with  porcelain  by  Dr.  Land.  The  right  central 
shows  the  porcelain  in  position,  and  the  left  the  porcelain  tip 
ready  to  be  adjusted. 

1  This  operation  was  performed  by  Dr.  Land  at  the  meeting  of  the  First  District 
Dental  Society  of  the  State  of  New  York,  in  January,  1889. 


CHAPTER    XV. 

FINISHING  AND  POLISHING— PROCESS  OF  CEMENTATION. 
FINISHING  AND  POLISHING  CROWN-WORK. 

The  finishing  should  be  done  with  small  corundum-wheels 
and  points,  first  coarse,  then  fine,  on  the  dental  engine,  which, 
for  this  part  of  the  work,  is  preferable  to  files  or  the  lathe.  In 
the  final  finishing  use  leather  polishing- wheels  with  fine  pumice  on 
the  engine,  or  felt  wheels  on  the  lathe ;  and,  in  the  polishing,  a 
brush  wheel,  with  whiting  and  rouge  on  the  lathe. 

The  gold  should  first  be  properly  shaped,  which  includes 
trimming  the  collar  off  to  a  fine  edge  where  it  fits  under  the 
gum,  so  that  the  seam  of  union  with  the  root  will  be  impercep- 
tible. The  gold  that  has  been  placed  on  the  incisive  edge  of  the 
incisor  and  cuspid  crowns  should  be  trimmed  away,  so  that 
although  it  will  protect  the  porcelain,  very  little  if  any  gold 
will  be  seen  when  the  crown  is  in  position  in  the  mouth. 

INSERTION    AND  CEMENTATION. 

In  the  insertion  and  cementation  of  all  crown-  and  bridge-work, 
the  object  to  be  effected  is  the  same  in  principle,  that  is,  to  form 
with  an  insoluble  material  a  solid,  substantial,  and  impervious 
union  between  the  natural  tooth  or  root  presented  and  the  arti- 
ficial crown. 

OXYPHOSPHATE  OF  ZINC. 

As  a  cement  for  this  purpose,  the  plastic  oxyphosphate  of 
zinc  is  generally  preferred,  and  it  is  in  many  respects  one  of  the 
most  suitable  that  has  been  found. 

Exact  scientific  proportions  of  the  chemical  substances  of  which 
the  cement  is  composed  are  essential  in  its  preparation.  The 
oxide  of  zinc  should  have  been  calcined  at  a  high  heat,  and  then 
ground  to  a  very  fine  powder.     It  should  possess  the  property 

11  146 


146  ARTIFICIAL  CROWN-  AND  BRIDOE-WORK. 

of  being  uniformly  dense  and  hard  clear  through  the  center, 
when  set,  after  being  mixed  thin  and  formed  in  a  mass. 

The  setting  of  the  best  preparations  of  pure  oxyphosphate  of 
zinc  is  materially  affected  by  temperature.  Thus,  a  cement 
which  is  slow-setting  at  40°  F.  is  apt  to  be  quite  quick-setting 
;it  80°  F.  In  some  of  the  preparations  of  cement,  an  effort  is 
made  to  remedy  this  variation  by  adulterating  with  various  sub- 
stances, but  this  tends  to  increase  the  solubility  of  the  compound. 
A  standard  preparation  of  cement,  answering  the  requirements 
previously  outlined,  should  be  used  in  crown-  and  bridge-work. 
For  all  styles  of  crowns  with  collars,  and  for  bridge-work  de- 
pending on  crowns  of  similar  construction,  the  cement  should 
be  mixed  thin;  but  for  crowns  without  a  ferrule  or  collar  it  can 
be  moderately  thick.  For  mixing  the  cement,  a  piece  of  plate- 
glass  about  five  inches  long  and  three  inches  wide  as  a  slab,  and  a 
small  spatula,  are  suitable.  The  surface  of  the  slab  must  be  per- 
fectly clean.  The  acid  and  powder  should  first  be  separately 
placed  on  the  glass,  the  amount  of  powder  being  fully  equal  to 
the  requirements  of  the  acid.  A  portion  of  the  powder  should  be 
drawn  over  and  mixed  with  the  acid,  and  then  more  of  the  powder 
added,  a  little  at  a  time,  until  a  suitable  consistence  is  reached, 
when  the  surplus  powder  should  be  instantly  thrown  off  the 
slab,  and  the  mixing,  which  must  be  rapid  and  thorough,  con- 
tinued; the  consistence  should  be  that  of  thick  cream.  It  is  not 
a  good  plan  to  mix  cement  excessively  thin,  and  then  wait  until 
it  becomes  thickened  by  the  process  of  setting  to  a  consistence 
suitable  for  use,  as  the  resulting  compound  is  unnecessarily  acid, 
the  overplus  of  acidity  being  proportioned  to  the  excess  of 
acid  used  over  the  quantity  required.  If  the  slab  is  placed  on  a 
towel  which  has  been  saturated  with  ice-water,  the  cold  will 
retard  the  setting,  which  is  quite  an  advantage  in  many  cases. 
In  this  respect  the  side  of  a  square  bottle  filled  with  ice-water 
and  well  corked  is  preferable  to  a  slab. 

The  parts  to  be  crowned  should  be  previously  syringed  with 
water,  then  protected  by  a  napkin,  bathed  with  alcohol 1  applied 

1  Alcohol  used  in  this  manner  not  only  aids  in  drying  the  parts,  but  acts  as  a 
styptic  on  any  lacerated  portion  of  the  gingival  margin. 


INSERTION  AND  CEMENTATION.  147 

on  cotton  with  tweezers,  and  wiped  with  bibulous  paper.  Each 
cap  or  crown,  which  should  have  been  thoroughly  dried,  is  first 
filled  with  enough  cement  to  insure  a  slight  surplus.  A  small 
portion  is  then  put  in  each  root-canal  or  hollow  part  of  a  natural 
crown  present,  and  the  artificial  crown  or  bridge  immediately 
adjusted  in  position.  In  many  cases  it  is  best  to  quickly  remove 
the  napkin  and  close  the  mouth  to  insure  the  occlusion  of  the 
teeth,  and  then  open  the  mouth  and  replace  the  napkin.  The 
crown  or  bridge  should  be  held  under  a  slight  pressure  until 
the  cement  has  set.  For  this  purpose  a  piece  of  wood  notched 
on  the  end  or  an  adjuster  (Fig.  309)  can  be  used.    With  bicuspids 

Fig.  309. 


or  molar  crowns,  however,  it  is  better  in  most  cases  to  occlude  the 
teeth,  and  keep  them  in  position  until  the  cement  sets.  Under 
these  circumstances  the  saliva  can  reach  only  the  surplus  portion 
of  the  cement,  and  cannot  interfere  with  that  under  the  cap  or 
crown.  One  or  two  thicknesses  of  tin  foil,  placed  over  the  crown 
as  the  teeth  are  occluded,  will  slightly  favor  the  length. 

When  the  cement  has  set  perfectly  hard,  the  surplus  around 
the  edo-es  should  be  removed.  In  collar  or  shell  crowns  the 
edges  of  the  gold  of  the  collar  or  shell  should  be  given  a  final 
burnishing.  Wet  floss  silk  or  dental  fiber,  charged  with  pumice, 
should  be  passed  between  and  around  the  teeth  to  remove  every 
particle  of  the  superfluous  cement,  and  finally  the  parts  should 
be  syringed  with  tepid  water. 

The  patient  should  be  requested  to  call  in  a  few  days,  so  that 
an  examination  may  be  made  to  see  if  any  particles  of  the  cement 
were  overlooked.  Cleansing  gently  at  this  time  facilitates  the 
healimr  of  the  sum  around  the  collar  or  neck.  Care  in  these 
little  details  tends  to  prevent  that  inflamed  appearance  and  reces- 
sion of  the  gum  often  seen  around  crowns,  and  also  insures  a 
satisfactory  result  to  the  patient  and  commendation  to  the  dentist. 

Previous  to  insertion  the  posts  of  crowns  should  be  slightly 


148  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

barbed.  In  all-gold  cap-crowns  a  vent  for  the  escape  of  air  and 
surplus  cement  is  made  in  the  form  of  a  small  hole  usually  in  the 
deepest  fissure  of  the  grinding-surface  by  some,  but  is  generally 
considered  unnecessary.  When  the  cement  has  hardened,  the 
hole  must  in  all  cases  be  closed  with  a  gold  or  amalgam  filling. 

GUTTA-PERCHA. 

When  gutta-percha  is  used  for  cementing,  the  cavity  in  the 
root  and  crown  having  been  moistened  with  chloroform  and  then 
dried  and  heated  by  a  hot-air  syringe,  a  portion  of  the  gutta- 
percha is  inserted  and  caused  to  adhere  to  the  sides.  The  post 
and  the  crown  are  then  heated,  the  proper  quantity  of  the  gutta- 
percha attached,  and  the  crown  inserted.  When  the  gutta-percha 
is  cold,  the  surplus  is  removed  with  a  sharp  instrument,  and  the 
edges  smoothed  by  drawing  back  and  forth  against  them  some 
twisted  fibers  of  cotton  saturated  with  chloroform.  Sometimes 
the  post  can  be  fastened  with  oxyphosphate  and  the  end  of  the 
root  and  artificial  crown  joined  with  gutta-percha.  In  such  a 
case  the  crown  should  be  heated  and  the  gutta-percha,  rolled 
down  very  thin,  placed  on  the  edges  to  be  united  in  the  form  of 
a  perforated  disk.  The  crown  is  then  pressed  to  position  in  the 
oxyphosphate  placed  in  the  root.  The  order  of  the  use  of  these 
materials  can  be  reversed  where  it  may  be  desirable  at  some 
future  time  to  easily  remove  the  crown.  Bridge-work  can  be 
conveniently  attached  temporarily  with  gutta-percha.  In  this 
event  a  quantity  barely  sufficient  to  fasten  the  caps  should  be 
used.  Gutta-percha  does  not  possess  sufficient  rigidity  for 
general  use  in  bridge-work. 

AMALGAM. 

Amalgam  is  used  to  some  extent  to  support  and  retain 
porcelain  crowns.  Its  use  in  connection  with  the  Bonwill  crown 
is  given  on  page  47.  Where  it  is  desirable  to  use  amalgam 
Dr.  Kirk  gives  copper  amalgam  the  preference  to  other  kinds  for 
attachments  of  the  Logan  crown  on  weak  or  badly  decayed  roots. 
The  following  is  Dr.  Kirk's  method  for  the  adjustment  of  Logan 
and  similar  classes  of  crowns,  which  he  has  found  extremely 
satisfactorv  in  cases  where  there  has  been  much  loss  of  root- 


INSERTION  AND  CEMENTATION.  149 

structure  through  the  action  of  caries  in  the  pulp-canal,  resulting 
in  a  large  funnel-shaped  opening  with  more  or  less  weakened 
root-walls. 

The  canal  is  prepared  by  removing  the  softened  structure, 
filling  the  apex,  and  making  suitable  undercuts  or  roughnesses 
along  its  walls,  and  then  filled  flush  with  its  orifice  with  a  good 
grade  of  copper  amalgam  softened  to  a  plastic,  buttery  condition. 
The  apical  end  of  the  crown  pin  is  sharpened  to  a  point  or  hatchet 
edge  as  may  be  most  expedient,  and  placed  against  the  amalgam 
surface  in  the  root-opening,  and  the  crown  at  once  driven  to 
place  in  close  contact  with  the  root  by  holding  against  its  morsal 
(occluding)  surface  a  suitable  point  mounted  in  the  Bonwill 
mechanical  mallet.  For  this  purpose,  the  blow  of  the  mallet 
should  be  considerably  increased  in  intensity  beyond  that  ordi- 
narily used  for  filling-operations.  The  point  used  in  the  mallet 
for  driving  the  crown  home  is  best  improvised  from  a  porte 
polisher  armed  with  a  hickory  point,  the  use  of  which  avoids 
chipping  the  porcelain.  All  excess  of  copper  amalgam  is  by 
this  means  driven  out  between  the  surfaces  of  contact  of  the 
crown  and  root  in  precisely  the  same  manner  as  occurs  in  the 
use  of  oxyphosphate.  An  excess  should  be  used  in  order  to  be 
sure  of  filling  all  interstices.  This  method,  involving  the  use 
of  copper  amalgam,  is  advocated  only  in  the  class  of  cases  de- 
scribed, for  which  it  possesses  the  advantage  of  giving  complete 
support  to  the  root,  because  of  the  great  strength  and  insolubility 
of  the  material  employed.  Other  amalgams  experimented  with 
for  this  purpose  have  not  been  so  satisfactory,  because  of  their 
lack  of  plasticity,  and  of  the  flowing  quality  which  characterizes 
the  copper  amalgam  when  subjected  to  the  rapid  vibratory  per- 
cussive force  of  the  mechanical  mallet  blow. 


PART  111. 


BRIDGE-WORK. 


BRIDGE-WORK 


The  artificial  replacement  of  the  loss  of  a  portion  of  the  teeth 
by  bridging  the  vacant  spaces  with  substitutes,  supported  in  posi- 
tion by  means  of  their  attachment  to  adjoining  or  intervening 
natural  teeth,  is,  as  we  have  seen  in  the  introduction,  of  antique 
origin,  having  been  practiced  long  before  plates  came  into  use. 


Fig.  310. 


Fig.  311. 


Originally,  the  application  and  mechanical  construction  of 
such  dentures  was  of  a  most  primitive  character;  and  as  the 
attachments  were  simply  ligatures  or  clasps  of  gold,  the  teeth 
were    more    ornamental    than  F      „12 

useful.  Figs.  310,  311,  and  312 
illustrate  the  antique  methods.1 
Fig.  310  is  an  illustration  of  a 
specimen  of  ancient  Phoenician 
dentistry.  Fig.  311  is  that  of 
one  in  the  Etruscan  age,  dating  about  five  hundred  year-  B.C. 
Fig.  312  gives  a  view  of  the  same  denture  inverted. 

Dentures  constructed  on  the  bridging  plan  by  various  methods 
have  been  occasionally  employed  from  the  earliest  days  of  modern 

'See  Independent  Practitioner,  vols,  vi  andvii,  "  Evidences  of  Prehistoric  Den- 
tistry," by  J.  G.  Van  Marter,  D.D.S  ,  Rome,  Italy.  Figs.  310,  311,  312 are  copies 
of  the  illustrations  of  the  specimens,  the  first  of  which  is  represented  as  being 
in  the  museum  of  the  Louvre,  Paris,  France,  and  the  second  in  the  Corneto 
Museum,  Corneto,  Italy. 

153 


154 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


dentistry,  though  until  recent  years  the  system  has  not  obtained 
general  recognition  nor  been  extensively  practiced. 

Dental  literature  presents  bridging  operations  as  described  by 
J.  B.  Gariot  in  1805,  C.  F.  Delabarre  in  1820,  Dr.  S.  S.  Fitch  in 
1829,  William  Imrie  in  1834,  J.  Paterson  Clark  in  1836,  and  Dr. 
W.  H.  Dwinelle  in  1856.  Figs.  313  and  314  are  copies  of  illustra- 
tions in  Dr.  Fitch's  work,  published  in  New  York  in  1829,  and 
Fig.  315  one  from  a  translation  of  F.  Maury's  work  in  1843. 
In  1871  the  bridging  process  or  bridge  principle  was  again 
brought  to  notice  by  a  patent  applied  for  in  England  by  Dr. 
B.  J.  Bing,  of  Paris,  for  an  improved  means  of  supporting  and 


Fig.  313. 


Fig.  314. 


Fig.  315. 


Fig.  316. 
c    c     cl  cc   a  c  c 


securing  a  bridge  by  anchoring  with  cement  or  fillings  clasps  or 
bars  extending  from  it  into  holes  formed  in  the  adjoining  teeth 
(Fig.  316).  The  system  was  also  practiced  in  operations  by  the 
late  Dr.  M.  H.  Webb,  and  is  described  in  his  "  Notes  on  Opera- 
tive Dentistry." 

The  facilities  afforded  by  the  artificial  crown-work  now  in 
vogue  for  supporting  and  securing  bridge  dentures  have  caused 
a  revival  of  the  system  in  an  improved  form,  termed  "  Bridge- 
Work,"  in  which  artificial  crowns  cemented  to  natural  teeth  or 


BRIDGE- WORK.  155 

roots  are  employed  as  abutments  to  support  artificial  teeth  which 
span  or  bridge  the  spaces  between  them.  These  bridges  are  so 
devised,  in  the  best  methods,  that  while  supplying  the  patient, 
with  the  means  of  masticating  his  food  the  cleanliness  of  the 
denture  is  also  provided  for. 

Ordinarily,  bridge-work  is  immovably  cemented  in  position. 
The  claims  set  up  in  its  favor  are  as  follows : 

First.  The  perfect  replacement  of  lost  teeth  b}7  artificial  ones, 
and  without  the  use  of  a  plate. 

Second.  The  absence  of  any  mechanical  contrivance  to  inter- 
fere with  the  tongue  in  articulation. 

Third.  The  natural  teeth  are  not  abraded  by  the  presence  of 
clasps,  the  functions  of  the  sense  of  taste  are  more  perfectly 
performed,  and  a  healthy  condition  of  the  tissues  preserved, 
because  the  gums  and  palate  are  not  covered  over  with  a  plate. 

Fourth.  The  solidity  and  immovability  of  the  denture  at  all 
times,  both  in  speech  and  mastication. 

Fifth.  The  weight  of  the  denture  and  the  strain  of  mastica- 
tion are  proportionately  distributed  on  the  natural  teeth,  which 
are  better  suited  to  sustain  them  than  the  contiguous  alveolar 
surfaces. 

Sixth.  Its  special  adaptation  to  the  replacement  of  single 
teeth,  or  of  a  small  number,  where  bridge-work  is  usually 
superior  to  any  other  device. 

Seventh.  While  all  operations  performed  for  the  restoration 
of  lost  teeth,  like  other  remedial  operations,  are  temporary  rather 
than  permanent  in  their  results,  bridge-work  as  regards  per- 
manency takes  equal  rank  with  any  other  operative  procedure. 

The  following,  on  the  other  hand,  are  the  objections  raised 
against  bridge-work  : 

First.  It  fails  to  restore  the  contour  of  the  soft  tissues  above 
the  bridge,  as  artificial  gums  cannot  properly  be  used  in  this 
style  of  work. 


156  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

Second.  The  slots  beveled  under  the  artificial  teeth,  called 
self-cleansing  spaces,  fill  with  particles  of  food. 

Third.  The  speech  of  the  wearer  is  often  affected  by  these 
self-cleansing  slots  under  the  front  teeth. 

Fourth.  The  teeth  employed  as  abutments  are  usually  irre- 
parably destroyed  by  the  process  of  crowning. 

Fifth.  If  an  extensive  bridge  is  made  of  gold,  being  im- 
movable, it  is  impossible  to  keep  it  perfectly  clean,  as  the  metal 
will  gradually  tarnish  in  parts  out  of  reach  of  the  brush,  and 
will  gather  offensive  matter  on  its  surface  and  in  its  interstices. 

Sixth.  In  cases  where  it  becomes  necessary  to  temporarily 
remove  the  bridge  for  the  purpose  of  repair,  or  because  of  dis- 
ease in  the  teeth  which  support  it,  the  operation  is  difficult  and 
the  bridge  is  usually  injured  so  as  to  unfit  it  for  reinsertion. 

Seventh.  The  teeth  which  support  the  bridge  are  required  to 
bear  more  force  and  pressure  than  nature  intended, — where  the 
piece  is  large  many  times  more, — and,  the  bridge  being  perma- 
nently attached,  at  no  time  can  any  rest  be  given  the  abutments  or 
the  contiguous  parts  by  its  temporary  removal.  Thus  in  a  piece 
of  bridge-work  of  fourteen  teeth  supported  by  caps  or  crowns 
on  four  natural  ones,  each  one  of  the  natural  teeth  may  have  to 
bear  more  than  three  times  the  strain  in  supporting  the  weight 
of  the  denture  and  the  force  of  mastication,  that  was  intended. 
The  ultimate  result  is  evident  to  any  one  who  is  experienced 
in  dental  practice  ;  and  unless  the  anatomical  conditions  are 
most  favorable,  the  usefulness  and  durability  of  such  work  is 
decidedly  limited  in  character,  considering  the  time,  trouble, 
and  great  expense  attending  it. 

Such  are  the  objections  which  have  been  put  forth  against 
bridge-work ;  and  yet,  whatever  may  be  urged  against  it,  its 
advantages  have  won  from  a  majority  of  the  profession,  includ- 
ing many  accepted  authorities,  an  enthusiastic,  almost  a  sen- 
sational, indorsement;  some  practitioners  even  going  so  far  as 


BRIDGE-WORK.  157 

to  proclaim  it  the  only  true  method  for  the  insertion  of  artificial 
teeth. 

Judged  impartially,  bridge-work  has  many  advantages  when 
practiced  by  experts  who  properly  construct  and  apply  it. 
Without  doubt  it  has  been  abused.  Bridges  have  been  inserted 
where  the  support  was  insufficient,  or  the  construction  was  wrong 
in  principle  or  faulty  from  lack  of  skill.  More  than  this  :  bridge- 
work  has  been  passing  through  the  experimental  period,  when 
failures  are  apt  to  appear  more  prominently  than  successes. 
The  chronicles  of  dental  literature,  however,  in  this  respect  offer 
only  a  repetition  of  the  historical  difficulties  that  attend  all  new 
departures  in  the  arts. 


CHAPTER    I. 

CONSTRUCTION  OF  BRIDGE-WORK. 

To  the  skilled  mechanical  dentist,  well  versed  in  metal-  and 
crown-work,  bridge-work  does  not  present  extreme  difficulty. 
The  foundations  or  abutments — that  is,  the  teeth  or  roots  on 
which  the  bridge  will  rest — are  first  to  be  considered,  due  respect 
being  paid  to  the  mechanical  principles  controlling  the  leverage 
and  the  force  of  occlusion  in  mastication.  The  amount  of  strain 
that  can  be  borne  by  the  different  teeth,  individually  and  collect- 
ively, according  to  their  position  and  condition  of  health,  should 
be  carefully  calculated.  As  a  rule,  the  force  exerted  upon  the 
incisors  in  occlusion  will  be  directed  outward  on  the  upper,  and 
inward  on  the  lower  teeth,  and  its  tendency  when  they  support 
a  bridge  will  be  to  gradually  push  them  out  of  line  in  each  direc- 
tion. When  the  incisors  are  replaced  by  a  bridge,  the  tendency 
of  the  force  of  occlusion  is  toward  a  similar  result.  On  the 
bicuspids  and  molars  the  force  is  direct.  The  rules  which  govern 
the  number  and  position  of  the  teeth  or  roots  that  are  required 
as  foundations  for  bridges  in  practice,  are  as  follows : 

One  central  root  will  support  two  centrals,  and  if  spurs  or 
bars  from  the  sides  of  the  bridge  rest  upon  or  are  anchored  in 
the  adjoining  teeth,  a  lateral  in  addition. 

Two  central  roots  will  support  the  four  incisors,  spurs  or  bars 
resting  on  or  anchored  in  the  cuspids  to  be  used  additionally,  if 
the  case  requires  them. 

The  cuspid  roots,  alone,  or  with  the  aid  of  a  central  root,  will 
support  the  six  anterior  teeth. 

One  molar  or  bicuspid  on  one  side,  and  a  bicuspid  or  molar 
on  the  other,  with  one  or  two  roots  in  an  intermediate  position, 
will  support  a  bridge  between  them. 

One  right  and  one  left  molar,  with  the  assistance  of  the  two 
cuspids,  will  support  a  bridge  comprising  the  entire  arch. 

A  bridge  on  one  side  of  the  mouth  can  be  supported  by  two 

158 


CONSTRUCTION  OF  BRIDGE- WORK. 


159 


or  three  teeth  or  roots  on  that  side.     The  cuspids  always  aftord 
the  most  reliable  support. 

In  general,  the  application  of  these  principles  will  cover  the 
subject  of  foundations,  the  operator  being  governed  by  the  exact 
condition  of  individual  cases.  In  a  bridge  of  the  six  anterior 
teeth  on  the  two  cuspids,  when  the  articulation  of  the  antago- 
nizing teeth  is  close  and  deep,  the  strain  should  be  relieved  by  an 
additional  attachment  of  the  bridge  to  the  teeth  posterior  to  the 
cuspids. 

Fig   317. 


The  preparation  of  teeth  or  roots  to  support  a  bridge  is  the 
same  as  for  ordinary  crowns,  except  that  the  trimming  of  the  sides 
and  the  drilling  of  the  root-canals  of  the  various  anchorages 
should  be,  as  far  as  possible,  in  parallel  lines,  so  that  the  collars 
and  posts  of  the  crowns  shall  move  readily  to  their  places  in  the 
adjustment  of  the  finished  bridge.  Teeth  or  roots  which  are  to 
be  supplied  with  all-gold  cap-crowns  are  crowned  by  some  one 
of  the  methods  already  described.  Those  on  which  porcelain 
fronts  are  to  be  used  are  merely  capped,  the  posts  being  soldered 
and  allowed  to  project  a  short  distance  beyond  the  caps. 

The  case  represented  in  Fig.  317  will  be  used  to  illustrate  the 
construction  of  a  piece  of  bridge-work  in  all  its  details.  The 
abutments,  or  supports,  consist  of  the  right  second  molar  capped 
with  an  all-gold  crown,  constructed  in  sections  by  first  forming 


160 


ARTIFICIAL  CROWN-  AND  BRIDQE-WORK. 


the  collar  and  then  soldering  on  the  cap  (see  page  92),  the  two 
cuspid  roots  capped  for  collar  crowns  with  porcelain  fronts  (see 
page  85),  and  the  left  first  molar,  which  will  afford  anchorage 
to  a  bar  on  that  side  of  the  bridge  (Fig.  318).  A  slot,  dovetail 
in  form,  is  usually  cut  well  into  the  body,  but  not  to  an  extent 
that  will  endanger  the  pulp  of  the  last-named  crown  (Fig.  319). 
If  the  tooth  is  not  decayed,  it  can  be  first  opened  up  with  a 
rubber  and  corundum  disk.  The  shaping  of  the  slot  is  best 
accomplished  with  fissure-burs.  With  the  crowns  and  caps  in 
position,  an  impression  and    articulation  of  the  case  are  then 


Fig.  318. 


Fig.  319. 


taken  with  plaster1  slightly  colored  with  carmine.  The  plaster 
is  mixed  moderately  thick  and,  with  the  aid  of  a  spoon,  placed 
around  in  the  mouth  on  the  crowns,  caps,  and  parts  to  be 
included  in  the  bridge,  and  the  antagonizing  teeth  occluded 
tightly  and  so  held  until  the  plaster  sets.  The  mouth  is  then 
opened  and  the  plaster  carefully  removed,  the  pieces  being 
adjusted  together  should  it  break.  The  crowns  and  caps  (the 
latter  held  more  firmly  by  the  protruding  ends  of  the  pins)  are 
removed  in  it.  The  plaster  is  then  varnished,  and,  on  the  side 
containing  the  crowns,  a  model  is  run,  composed  of  equal  parts 


1  Impression  compound  is  used  to  some  extent  for  this  purpose  instead  of  plaster, 
but  in  the  author's  opinion  cannot  be  recommended  as  suitable. 


CONSTRUCTION  OF  BRIDGE- WORK. 


161 


of  calcined  marble-dust  and  plaster,  to  which  is  added  a  little 
sulphate  of  potassium, — less  than  the  proportion  of  salt  generally 
used, — which  causes  the  mixture  to  set  hard  quickly.  When  the 
model  has  set,  it  is  mounted  with  plaster  on  an  articulator,  and 
the  other  side  of  the  colored  plaster  impression  giving  the 
articulation  is  run  with  plaster  and  the  opposite  section  of  the 
articulator  adjusted,  all  at  the  same  time.  When  the  impres- 
sion plaster  is  removed  (an  operation  which  is  greatly  facilitated 
by  its  having  been  colored  with  carmine),  a  correct  model  and 
articulation  of  the  case  will  be  found,  with  the  crowns  and 
caps  in  exact  position  as  in  the  mouth  (Fig.  320). 


Fig.  320. 


Another  method  is  to  first  take  the  impression  in  an  impression- 
tray,  and  then  the  articulation  in  wax,  and  make  a  model  and 
articulation  from  tbem  in  the  usual  manner. 

Dr.  Melotte's  method  is  to  place  a  piece  of  impression  com- 
pound in  the  space  between  the  crowns  to  be  occupied  by  a 
bridge,  and  occlude  the  teeth.  The  compound  is  then  chilled,, 
removed,  trimmed,  and  readjusted  until  it  accurately  fits  the 
space,  when  it  is  placed  in  position  and  an  impression  is  taken 
with  plaster.  When  the  impression  is  removed,  iron  pins  to  act 
as  dowels  are  placed  in  the  portions  representing  the  natural 
teeth,  and  then  several  pieces  of  fusible  metal,  by  a  few  puffs  of 
flame  from  the  blow-pipe,  are  melted  in  around  the  pins.  The 
rest  of  the  impression  is  then  run  with  plaster  and  marble-dust 

12 


162 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


in  the  usual  manner.  This  forms  a  plaster  model  on  which  the 
natural  teeth  are  represented  in  metal.  These  metal  teeth  are 
to  be  removed  before  investing  in  soldering  the  bridge.  An 
impression  of  the  occluding  teeth  is  taken  in  plaster,  and  the 
entire  impression  run  with  fusible  metal.  When  the  plaster 
impression  is  removed  from  the  model  of  the  bridge,  the  piece 
of  impression  compound  between  the  crowns  is  to  be  left  in 
position,  and  the  metallic  model  of  the  occluding  teeth  fitted  in 
position,  guided  by  the  indentations  of  the  occluding  teeth  in 
the  compound,  and  the  case  mounted  on  an  articulator.  The 
principal  object  of  this  method  is  to  avoid  fracture  of  forms  of 
natural  teeth,  both  in  removal  from  impressions  and  in  the  con- 
struction of  the  bridge-work. 

The  pins  protruding  from  the  caps  on  the  model  are  next  cut 
off  short.  Teeth  are  selected, — ordinary  cross-pin  plate  teeth 
for  the  incisors  and  cuspids,  and  partial  teeth,  representing  the 
front  section  of  the  tooth  and  styled  porcelain  facings,  which 
were  specially  designed  for  crown-  and  bridge-work,  for  the 
bicuspids  and  molars  (Fig.  321).     Cuspids  are  sometimes  used 

to  form  the  fronts  for  bicuspids. 
The  teeth  are  ground  and  fitted 
to  the  model  and  articulation,  so 
that  the  labial  upper  edge  of  the 
teeth  shall  press  lightly  on  the 
gum.  Those  which  are  intended 
to  form  the  fronts  of  the  caps  on 
the  cuspid  roots  should  be  ad- 
justed in  the  ordinary  manner  for 
single  crowns.  To  determine  the 
proper  positions  of  the  teeth  for 
producing  the  best  appearance, 
they  can  be  adjusted  in  the  mouth 
on  wax,  without  the  gold  crowns  or  caps  of  the  supports.  The 
correct  position  of  the  teeth  on  the  model  having  been  obtained, 
investing  material,  composed  of  one  part  plaster  to  two  of  cal- 
cined marble-dust,  is  placed  on  the  outside  of  the  model  on  the 
labial  aspect  of  the  teeth,  merely  sufficient  in  quantity  to  hold 
them  in  position,  thus  forming  a  matrix',  or,  the  matrix  can  be 


Fiq.  321. 


CONSTRUCTION  OF  BRIDGE- WORK. 


163 


formed  of  plaster  and  entirely  removed  before  investing  for  sol- 
dering. The  wax  is  then  removed,  exposing  the  palatal  portion, 
and  permitting  their  form  and  position  to  be  studied  (Fig.  322). 
The  porcelain  teeth  or  fronts,  with  the  exception  of  fronts  for 
the  roots  capped,  are  then  removed  from  their  investment,  and 
the  base  ground  from  a  line  on  the  palatal  side  below  the  pins, 
straight  to  the  labio-cervical  edge  (A  and  B,  Fig.  322).    This  is  to 

Fig.  322. 


A,  central  incisor,  and  B,  bicu-pid,  reaiy  for  metallic  backing.  C,  is  acentral  backed. 
D.  D,  D.  porcelain  fronts  as  they  appear  on  insertion  after  the  process  of  backing,  capping,  and 
soldering. 

form  the  self-cleansing  spaces.  The  incisors  are  then  backed, 
using  either  very  thin  platinum  or  pure  gold  (C).  The  backings 
are  allowed  to  extend  just  over  the  incisive  edge  as  a  protection  to 
it,  and,  if  preferred,  down  on  the  curve  of  the  self-cleansing  space. 
A  more  desirable  result  is  secured  if  the  backing  extends  only 
to  the  edge  of  the  self-cleansing  space,  and  the  porcelain  is  pol- 
ished, as  its  surface  is  superior  in  cleanliness  to  that  of  gold.  If 
the  platinum  backing  used  is  so  exceedingly  thin  as  to  be  of  the 
nature  of  foil,  it  is  advisable  to  rivet  a  small  piece  of  gold  plate 
>over  it  on  the  back  of  the  tooth,  to  insure  against  melting  the 


' 


164 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


platinum  oft'  the  porcelain  with  the  gold,  which  is  apt  to  occur 
if  a  pointed  flame  is  directed  against  it.  The  cuspids  are  backed 
in  the  manner  described  for  collar  crowns. 

The  bicuspid  and  molar  porcelain  fronts,  their  tips  being 
ground  off"  (A,  Fig.  323),  are  lined  in  a  similar  manner.  A  cap 
of  pure  gold  or  gold  lined  with  platinum,  representing  the 
grinding-surface  of  each  tooth,  is  struck  up  as  described  and 
illustrated  in  the  construction  of  gold  crowns  (see  page  96),  and 
the  concave  portion  filled  by  melting  in  scraps  of  20-carat  gold 
plate.  The  surface  is  then  ground  smooth  (B),  and  closely  fitted 
to  the  tip  of  the  porcelain  front  to  form  the  occluding  surface 
Fig.  323.  Fig.  324. 


^plP---B 


in  accordance  with  the  articulation  of  the  lower  teeth,  and  the 
space  filled  in  with  wax.  This  metallic  occluding  surface  is  to 
protect  the  porcelain.  Triangular  pieces  of  very  thin  gold  plate, 
platinum  foil,  or  mica  (C),  cut  and  fitted  to  the  sides,  over  which 
they  should  extend  slightly,  will  retain  the  gold  in  position  when 
melted,  but  seldom  are  necessary.  The  tooth  is  next  invested, 
leaving  the  back  open,  presenting  the  form  of  a  pocket  (Fig.  324). 
Fig.  325.  Another  method  of  constructing  bicuspid  and 

molar  dummies  is  to  fit  the  cap  to  the  labial  edge 
of  the  porcelain  front,  back  the  porcelain  with  thin 
platinum,  extending  the  backing  over  and  between 
the  porcelain  and  cap,  and  then  filling  in  the  space 
with  gold  in  soldering,  as  shown  at  A,  in  Fig.  325. 
The  bar  intended  to  be  anchored  in  the  slot  cut 
in  the  molar  on  the  left  side  is  made  of  iridio-plat- 
inum  wire,  about  ISTo.  15  IT.  S.  standard  gauge,  with 
the  end  shaped  as  shown  in  Fig.  326,  and  fastened 
with  wax  to  the  tooth  and  cap,  and  adjusted  in  the 
mouth  to  obtain  accuracy  of  position  before  soldering. 


CONSTRUCTION  OF  BRIDGE-WORK.  165 

The  advisability  of  constructing  bridge-work  with  what  are 
termed  self-cleansing  spaces  is  not  favorably  accepted  of  late  by 
many  practitioners.  Instead,  the  following  method  is  adopted  : 
Porcelain  fronts  thicker  in  the  line  from  the  labial  to  palatal 
side  than  those  most  commonly  used  are  selected.  The  base  or 
cervical  section  of  the  porcelain  is  ground  and  fitted  to  the 
alveolar  ridge  very  accurately.  The  fronts  are  then  waxed  in 
position,  and  with  a  fine-pointed  lead-pencil  a  line  is  drawn 
accurately  around  the  base  of  each  porcelain  front  on  the  model. 
The  fronts  are  then  removed,  and  with  a  suitable  scraper  the 
plaster  under,  and  only  under,  the  base  of  each  is  removed  uni- 
formly the  thickness  of  cardboard.  The  porcelains  are  then 
fitted  back  in  position  with  the  bases  in  the  indentations.  The 
work  is  then  proceeded  with  in  the  usual  manner.  When  the 
bridge  is  finished  and  inserted,  the  base  of  each  porcelain  will 
equally  indent  the  gum  to  the  depth  the  plaster  was  removed, 

Fig.  327.  Fig.  328. 


and  will  also  exclude  particles  of  food  and  present  a  much  more 
agreeable  appearance  for  the  patient.  The  shape  a  bicuspid 
dummy  would  assume,  constructed  as  described,  is  shown  in 
Fig.  325.1 

The  teeth  forming  the  bridge  between  the  crowns  are  called 
"  dummies."  In  the  construction  of  dummies  it  is  well  to  favor 
the  occluding  surface  by  shaping  it  a  trifle  narrower  from  labial 
to  palatal  side  than  the  corresponding  natural  tooth  was. 

All  the  porcelain  teeth  or  fronts  can  be  invested  at  the  same 
time,  including  the  incisors  and  porcelain  fronts  to  the  cuspid 
crowns,  as  shown  in  Fig.  327.  In  the  soldering,  if  the  backing 
is  done  with  platinum,  and  the  occluding  surface  of  the  bicuspids 

1  The  author,  at  present,  in  his  own  practice  constructs  his  work  in  this  manner. 


166 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


and  molars  made  with  gold  lined  with  platinum,  20-carat  gold 
plate  may  be  melted  into  the  pockets  formed  by  the  cap  and 
side  pieces  to  fill  out  to  the  line  at  A,  Fig.  328,  and  flowed  over 
the  backings  of  the  incisors  and  cuspid  fronts  in  sufficient  quan- 
tity to  shape  them  as  shown  atB,  Fig.  329.  When  the  backing 
and  occluding  surfaces  are  made  of  gold  plate,  20-carat  solder 
and  small  pieces  or  filings  of  gold  plate  should  be  used  instead. 
After  the  soldering  and  removal  of  the  borax  with  acid,  the 
metal  of  each  tooth  is  then,  when  it  is  easily  done,  very  carefully 
trimmed  and  shaped  with  corundum-wheels  and  points. 

The  teeth  are  next  placed  in  their  relative  positions  on  the 
model  as  shown  at  D,  D,  D,  Fig.  322,  and  attached  to  one  another 


Fig.  329. 


Fig.  330. 


with  wax  in  exactly  the  relation  and  only  where  they  are  to  be 
united  with  the  gold  solder.  The  model  is  then  detached  from 
the  articulator,  trimmed  down  as  much  as  possible  in  size,  and 
additional  investing  material,  composed  of  two  parts  marble- 
dust  and  one  of  plaster,  or  one  part  plaster,  one  marble-dust,, 
and  one  common  white  sand,  applied  until  all  of  the  bridge  is 
covered  except  the  space  along  the  backings  and  crowns  where 
they  are  to  be  united  in  the  soldering.  To  prevent  fracture 
during  the  process  of  soldering,  which  might  readily  occur  from 
contraction  in  so  large  an  investment,  an  iron  wire  or  a  narrow 
horse-shoe  shaped  strip  of  sheet  iron  should  be  placed  in  the 
investment  so  as  to  encircle  the  teeth  and  crowns  about  one- 


CONS  TR  UCTION  OF  BRIDGE-  WORK.  167 

fourth  of  an  inch  from  their  exterior  surface  (Fig.  330).  In  any 
spaces  between  the  backings  pieces  of  gold  or  platinum  plate  or 
wire,  about  one-eighth  of  an  inch  long,  are  placed  lengthwise, 
and  the  joints  well  soldered.  When  the  backings  have  been 
soldered  with  gold  plate,  20-carat  solder  may  be  used.  If  the 
backings  were  clone  with  20-carat  solder,  an  easy-flowing  18-carat 
solder  should  be  used.  The  soldering  is  best  done  with  a  gas 
blow-pipe  on  a  piece  of  charcoal  with  a  concave  depression. 
"When  the  bridge  is  removed  for  finishing,  the  joints  of  the 
backings  and  crowns  arc  finished  with  corundum-wheels  and 
points  and  leather  polishing-wheels  on  the  engine,  and  the  entire 
bridge  finely  polished  with  whiting  carried  by  a  brush-wheel  on 
the  lathe.  Any  little  pits  that  may  exist  can  be  filled  in  with  gold 
foil.  The  bridge  is  then  ready  for  insertion  (Fig.  331).  If  the 
constructive  details  have  been  v      „„, 

F  I G .    O  o  J  . 

properly  performed  as  described, 
a  finished  piece  of  bridge-work 
is  the  result. 

Pu  constructing  bridge-work 
many  prefer,  after  the  porcelain 
fronts  are  backed  and  the  caps 
forming  the  occluding  surfaces 
of  the  bicuspids  and  molars  are 
properly  adjusted  on  the  model, 
to  invest  and  do  the  entire  sol- 
dering at  once.  When  this  plan 
is  followed,  pieces  of  gold  wire  should  be  laid  lengthwise  in  the 
slots  under  the  gold  caps  of  the  porcelain  fronts,  and  the  parts 
filled  in  and  all  the  sections  of  the  bridge  joined  together  in 
the  soldering.  By  this  method  there  is  less  liability  of  frac- 
turing the  porcelain  fronts,  but  warping  is  more  apt  to  occur, 
and  the  finishing  of  the  bridge  is  not  so  easily  or  so  perfectly 
done. 

In  large  pieces  of  work  warping  may  be  avoided,  whichever 
method  of  soldering  is  adopted,  by  first  removing,  in  proper 
position,  the  "  dummies,"  and  soldering  those  of  each  span 
together.  The  spans  are  then  replaced  in  the  matrix  and  soldered 
to  the  abutments. 


168  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

Adjustment  and  Attachment.— The  bridge  when  finished  is  ad- 
justed in  the  mouth,  every  point  carefully  examined,  and  any 
alterations  required  are  then  made.  Should  the  edges  of  the 
collars  of  any  of  the  crowns  catch,  so  as  to  prevent  their  being 

Fig.  332. 


placed  in  position,  a  small  quantity  of  articulating  paste  should 
be  applied  and  the  point  found  and  trimmed  off.  If  extensive 
warping  has  occurred  in  the  soldering,  the  bridge  must  be  sawed 
apart  in  one  or  two  places,  adjusted  in  the  mouth,  and  removed  in 
an  impression-tray,  using  only  sufficient  investing  material  (equal 

parts  of  plaster  and  mar- 

FlG-  333-  i      i     .        v-u    +u  1 

ble-dust    with    the    usual 

quantity  of  sulphate  of 
potassium)  to  cover  the 
points  of  the  teeth  and 
crowns  (Fig.  332).  The 
inner  surface  of  the  tray 
should  be  oiled. 

The  bridge  and  the  in- 
vesting material  are  then 
removed  together  from  the 

impression-tray,  and  more  investing  material  is  added  to  complete 

the  investment.     The  cut  parts  of  the  bridge  are  then  soldered 

together. 

When  the  adjustment  of  the  bridge  is  accomplished,  it  can  at 

first  be  temporarily  inserted  for  a  day  or  two,  if  desired,  which 


CONSTRUCTION  OF  BRIDGE-WORK. 


169 


permits  it  to  settle  accurately  in  position.  Burnishing  the  col- 
lars will  usually  secure  it  for  this  purpose ;  if  not,  it  can  be 
attached  with  a  little  gutta-percha  placed  in  each  cap.  For  its 
permanent  attachment  the  pins  or  posts  of  the  crowns  are  barbed, 
and  the  teeth  and  roots  to  which  crowns  have  been  fitted  are 
then  treated  the  same  as  single  crowns,  and  the  bridge  cemented 
on  with  oxyphosphate  cement  (see  page  144).  The  end  of  the 
bar  is  anchored  in  the  slot  by  either  a  gold  or  an  amalgam  filling. 
Fig.  333  represents  the  bridge  in  position. 


The  Construction  of  Small  Pieces  of  Bridge-work  is  much  simplified 
by  the  following  method  :  Crowns  are  first  made  for  the  teeth  or 
roots  that  form  the  abutments  and  temporarily  placed  in  position. 
The  teeth — "dummies" — which  form  the  span,  having  been 
ground  and  backed,  are  adjusted  and  cemented  with  resin  and 
wax  in  proper  position  between  the  crowns.  The  crowns  and 
dummies  are  then  removed  together,  in  an  impression-tray  filled 
with  investing  material.  The  inside  of  the  tray  should  be  previ- 
ously oiled  or  coated  with  a  film  of  wax  with  a  serrated  surface. 
The  impression-tray  is  then  heated,  and  the  investment  with  the 
crowns  and  dummies  removed  ;  more  investing  material  is  then 
mixed,  and  the  exposed  parts  of  the  crowns  and  teeth  covered. 
The  investment,  when  set,  is  then  cut  away  sufficiently  to  expose 


170 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


the  parts  that  are  to  be  filled  in  and  united  together  in  the  pro- 
cess of  soldering.  Figs.  334,  335,  represent  cases  of  bridge-work 
constructed  in  this  manner. 


Fig.  335. 


In  a  bridge  of  two  teeth,  often  a  preferable  method  is  to  pro- 
perly adjust  crown  and  dummy  tooth  cemented  with  wax  in  the 
mouth,  carefully  remove  them  in  position,  then  invest  and  solder. 


CHAPTER  II. 


SPECIAL  PROCESSES  AND  APPLIANCES  IN  BRIDGE-WORE 


Fig.  336. 


Fig.  337. 


Shoulders  on  Anterior  Orowns  or  Artificial  Teeth  are  sometimes 
desirable,  especially  on  the  superior  cuspids  at  the  point  of 
occlusion  with  the  lower  teeth.  A  shoulder  can  be  made  by 
melting  gold  plate  into  the  form  of  a  small  ball  or  globule,  then 
flattening  it  out  and  soldering  it  against  the  backing. 

Another  method  is  to  attach  with, 
wax  transversely  across  the  backing 
in  proper  position  a  strip  of  gold 
plate  as  shown  in  Fig.  336,  and  then 
flow  in  gold  to  the  line  A,  by  spe- 
cially investing  or  in  the  soldering  of 
the  bridge.  The  strip  of  gold  should 
be  left  extending  a  little  on  both  sides  of  the  backing  so  that 
the  investment  will  retain  it  in  position,  or  the  gold  instead  can 
be  extended  over  the  incisive  edge. 

Solid  Gold  Grovms. — In  a  close  articulation,  when  the  patient 
prefers  strength  to  appearance,  the  bicuspids  and  molars  may 
be  made  of  solid  gold.  They  are  constructed  by  stamping  up 
the  cap  (A,  Fig.  337)  representing  the  grin  ding-surface  (see 
page  94),  adjusting  and  cementing  to  this  with  wax  a  piece  of 
plate  cut  and  shaped  to  form  the  front  and  sides  (B),  the  whole 
being  then  invested  and  filled  in  with  gold  solder,  or,  if  pure 
gold  and  platinum  has  been  used  in  the  sections  of  the  crown, 
with  18-  or  20-carat  plate. 

Seamless  contour  crowns  can  be  used  for  the  purpose  as 
follows  :  The  proper  crowns  having  been  selected,  the  gold  is 
trimmed  and  the  crowns  adjusted  in  position  on  the  model.  A 
matrix  of  plaster  is  then  placed  on  the  labial  side,  which  permits 
exposure  of  the  palatal  portion,  the  crown  removed,  and  cut 

171 


172 


ARTIFICIAL    CROWN-  AND  BRIDGE-WORK. 


away  to  the  form  required.  They  are  then  removed,  invested, 
and  filled  in  with  scraps  of  gold  plate  and  solder. 

A  bar-bridge  can  be  made  with  these  seamless  crowns  by 
passing  an  iridio-platinum  wire  through  the  crowns  before  filling 
in  (Fig.  338). 

A  Solid  Gold  Crown  for  a  Palpless  Molar,  supporting  the  end 
of  a  bar  as  shown  in  Fig.  339,  is  constructed  as  follows :  The 
natural  crown  is  ground  down,  banded,  capped,  and  pivoted  as 
in  Fig.  340.  The  gold  forming  the  top  of  the  cap  is  made  per- 
fectly fiat  and  left  projecting  a  little  at  the  sides.     A  contoured 

Fig.  338.  Fio.  339.  Fig.  340. 


crown  of  pure  gold,  or  gold  lined  with  platinum 
as  a  precaution  against  melting,  is  shortened  suf- 
ficiently to  represent  the  absent  coronal  section 
of  the  tooth,  and  with  a  corundum-disk  the  orifice  ^  "^ 
of  the  anchorage  cavity  is  formed.  A  shell  of  thin  platinum  of 
the  size  and  shape  of  the  anchorage  cavity  is  then  inserted  and 
cemented  with  wax  on  the  inside  of  the  crown.  The  crown  is 
then  invested  and  filled  with  18-carat  gold  solder,  which  should 
be  cut  into  small  pieces,  and  be  placed  successively  in  the  crown 

Fig.  341. 


and  melted  by  maintaining  a  uniform  heat  with  the  large  flame 
of  a  blow-pipe.  The  base  of  the  crown  is  next  ground  level  and 
accurately  fitted  to  the  cap  and  articulated  to  the  antagonizing 


SPECIAL  PROCESSES  AND  APPLIANCES  IN  BRIDGE-WORK.    173 


teeth.  It  is  then  clamped  in  position  to  the  cap.  the  pivots  of 
which  are  protected  with  investing  material  (Fig.  341),  and 
soldered,  making  a  perfect  joint.  This  is  an  easy  method  of 
constructing  an  otherwise  difficult  form  of  crown. 

Fig.  342  illustrates  a  bridge  supported  by  a  bar-anchorage  in 
a  solid  gold  crown  on  the  roots  of  a  molar,  and  a  shell  crown  on 
a  cuspid. 


Fig.  342. 


*c=% 


Fig.  343. 


Fig.  344. 


Fig.  345. 


Connecting  Bands  or  Bars  for  Bridges,  which  obviate  the  removal 
of  crowns  of  intervening  natural  teeth  between  the  sections  of  a 
projected  bridge,  are  formed  by  passing  a  heavy  band  of  oval- 
shaped  gold  or  iridio-plati mini  wire  around  the  intervening  teeth, 
close  to  but  not  touching  them,  and  resting  lightly  on  the  gums. 


174 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


The  application  of  this  device  was  first  illustrated  by  Dr.  J.  L. 
Williams,  Figs.  343,  344,  and  345. 

Intt  rvehing  Roots  between  the  abutments  of  a  projected  bridge 

Fig.  346. 


Fig.  347. 


should  not  be  extracted,  but  whenever  practicable  they  should 


SPECIAL  PROCESSES  AND  APPLIANCES  IN  BRIDGE-WORK.    175 

be  treated,  filled,  and  trimmed  level  with  the  gum,  as  they  can 
usually  be  made  to  afford  some  support  for  the  bridge,  which  may 
rest  upon  them.  Figs.  346  and  347  represent  a  case  in  which  the 
root  of  the  cuspid  on  the  right  side  has  been  so  treated  and  utilized. 

Shell  Anchorage  or  Grown. — A  shell  crown  or  anchorage  for  a 
cuspid  to  support  bridge-work  is  preferably  used  instead  of  a 
gold  collar  crown  with  porcelain  front,  where  the  insertion  of 
such  a  form  of  crown  involves  the  excision  of  a  natural  crown 
with  a  living  pulp.  A  convenient  method  of  construction  is  the 
following:  Shape  the  natural  crown  parallel  on  the  sides. 
Construct  and  adapt  to  the  cervix, 

and  slightly  under  the  gum-mar-        Fig.  348.  Fig.  349. 

gin  of  the  natural  crown,  a  gold 
collar  wide  enough  to  extend  a  little 
below  the  incisive  edge.  Remove 
a  portion  of  the  gold  from  the 
incisive  labial  section,  and  slit  the 
palatal  surface  on  both  sides  of  its 
center,  as  represented  in  Figs.  348  and  349.  The  part  at  A  is 
bent  back,  and  the  parts  at  B,  B  beveled,  hent  in  on  the  crown, 
and  burnished  close  to  its  surface.  The  piece  A  is  next  brought 
down  in  position,  and  adapted  to  the  crown  and  over  the  parts 
B,  B. 

The  collar  has  now  assumed  the  form  of  a  gold  crown  having 
an  open  face  and  seams.  The  seams  are  next  united  by  placing, 
melting,  and  flowing  solder  into  each  of  them,  a  little  at  a  time, 
by  holding  the  crown  with  tweezers  in  a  Bunsen  gas-flame. 
The  seams  will  hold  and  retain  solder  sufficient  to  join  and 
fill  them  without  its  flowing  over  the  adjacent  parts,  unless 
there  is  an  excess  of  heat  or  solder.  When  the  soldering  is 
completed,  the  crown  is  adjusted,  a  line  showing  the  exact 
portion  of  the  labial  aspect  to  be  exposed  marked  on  the 
gold,  the  crown  removed,  its  edges  trimmed  to  the  mark,  and 
the  soldered  parts  smoothed  with  corundum-wheels  and  points 
on  the  engine. 

Another  method  for  the  construction  of  a  shell  crown  prefer- 
ably practiced  by  some  is:  Fit  a  gold  collar  around  the  natural 
crown,  and  remove  the  gold  at  the  labial  aspect  as  shown  at  «, 


176 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


Fig.  350.  In  the  vacancy  between  the  collar  and  tooth  at  the 
palatal  side,  fit  and  burnish  a  piece  of  pure  gold  or  thin  platinum, 
which  will  cover  the  exposed  surface  of  the  tooth  at  that  part, 
and  fill  in  the  space  between  the  collar  and  piece  of  plate  with 


Fig.  350. 


wax  cement,  d,  Fig.  350,  shows  the  form  generally  of  the 
piece  of  plate  before  it  is  fitted  in  the  collar.  Remove  the  collar, 
invest,  and  flow  solder  into  the  space  between  the  piece  of  plate 
and  collar,  and  remove  the  surplus  gold  of  the  collar  extending 
above  the  crown ;  b  and  c  show  the  finished  shell  crown. 

A  Seamless  Shell  Anchorage  is  formed  as  follows :  From  an 
impression  of  a  natural  crown  taken  in  plaster,  gutta-percha,  or 
moldine,  a  die  in  fusible  metal  is  formed,  and  from  it  a  counter- 
die  in  lead  is  made.  (See  "  Gold  Seamless  Cap  Crown.")  On 
the  die  a  crown  is  stamped  from  a  seamless  cap  of  gold  (Fig.  351). 
This  crown  is  then  fitted  on  the  natural  tooth,  the  labial  aspect 
Fig.  351.  Fig.  352. 


of  which  is  exposed  by  the  removal  of  the  section  of  gold  cover- 
ing it  in  either  of  the  forms  shown  in  Fig.  352.  A  shell  for  a 
cuspid  can  be  made  from  a  gold  collar  as  well  as  a  cap.  The  shell 
formed  in  either  manner  is  then  filled  with  investing  material, 
and  strengthened  by  flowing  20-carat  solder  over  the  surface. 


SPECIAL  PROCESSES  AND  APPLIANCES  IN  BRIDGE-WORK.     177 

This  process  for  cuspids  lias  decided  advantages  for  the  easy 
formation  of  a  perfect-fitting  crown  or  shell  for  bridge-work. 

Fio-.  353  shows  the  forms  usually  given  shell  crowns  for 
bicuspids.     When  the  gold  is  removed  at  the  labio-cervical  part, 

Fig.  353.  Fig.  354. 


the  crown  should  be  additionally  secured  by  a  pin  introduced 
and  soldered  at  the  point  A. 

Fig.  354  illustrates  a  bridge  in  which  the  lower  incisors  are 
supported  by  shell  crowns  on  the  cuspids. 

In  cases  where  this  form  of  crown  is  expected  to  sustain  a 
great  strain,  the  gold  at  the  cervico-labial  section  should  be  re- 
inforced by  the  addition  of  a  strip  soldered  across  it  and  extend- 
ing around  on  the  sides. 

Fig.  355  represents  the  restoration  of  the  inferior  bicuspids 
and  molar  on  the  right  side,  by  a  bridge  with  a  shell  crown  on 

Fig.  355. 


the  cuspid  and  an  all-gold  crown  on  the  second  molar  as  abut- 
ments. 

Before  cementation  of  the  gold  crown  the  surface  of  the 
enamel  should  be  cleaned  with  pulverized  pumice,  wet  with 
aromatic  sulphuric  acid,  to  secure  a  better  adhesion  of  the 
cement. 


13 


CHATTER    III. 


EXTENSION  BRIDGES. 


This  term  is  applied  to  bridges  which  are  chiefly  supported 
by  one  abutment.  In  relation  to  the  anterior  teeth,  it  consists 
in  attaching  a  dummy  to  an  artificial  crown,  to  replace  an 
adjoining  absent  tooth.  A  bridge  of  this  style  replacing  two  or 
three  of  the  posterior  teeth  is  formed  by  using  two  of  the  teeth 


Fig.  356. 


Fig.  358. 


Fig.  357. 


Fig.  359. 


anterior  to  it  as  one  abutment,  with  a  saddle  for  the  other.  A 
saddle  is  an  oval-shaped  piece  of  gold,  of  the  form  of  the  gum 
and  a  little  larger  than  the  base  of  the  tooth,  placed  under  the 
posterior  tooth  of  the  bridge. 

Figs.  350  and  357  represent  an  extension  bridge.  A  crown 
on  the  cuspid,  an  all-gold  crown  on  the  bicuspid,  and  a  saddle, 
are  the  abutments.  In  constructing  this  bridge,  the  teeth  form- 
ing the  abutments  were  first  crowned.  The  crowns  were  then 
adjusted  in  position,  and  an  impression  and  articulation  taken  in 
178 


EXTENSION  BRIDGES. 


179 


plaster,  in  which  the  crowns  were  removed.  From  this  impres- 
sion a  model  was  made  of  plaster  and  marble-dust,  and  an 
articulation  in  plain  plaster.     With  the  crowns  in  position  on  the. 


Fig.  360. 


Fig.  362. 


Fig.  361. 


Fig.  303. 


Fig.  364. 


model  as  in  the  mouth,  the  bridge  was  then  constructed  by  the 
methods  described  on  page  162.  The  part  of  the  model  on 
which  the  saddle  rested  was  marked,  and  enough  of  the  surface 
of  the  plaster  removed  to  cause  the  saddle  to  press  tightly 
■against  the  soft  tissues  when  the  bridge  should 
be  completed  and  inserted  in  the  mouth. 

A  shell  crown  on  a  cuspid  can  be  used  as  an 
abutment  in  this  style  of  bridge,  instead  of  ex- 
cising the  natural  crown  and  mounting  an  arti- 
ficial crown  on  the  root  for  the  purpose  (Figs. 
358,  359). 

Figs.  360  and  361,  362  and  363,  represent 
small  extension  bridges  of  frequent  construction, 
the  former  to  repair  losses  in  the  anterior  portion  of  the  mouth, 
the  latter  to  replace  posterior  teeth.     Fig.  364  shows  a  pin  shell 
crown  which  can  be  made  to  support  a  porcelain  front  represent- 
ing a  cuspid  or  bicuspid. 

Figs.  365,  366,  and  367  represent  an  extension   bridge  con- 
structed bv  Dr.  II.  A.  Parr.     The  anterior  abutment  consists  of 


180 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


the  six  front  teeth,  which  were  all  crowned  and  joined  together, 
the  pulps  being  preserved  in  the  incisors.  A  saddle  on  each  side 
forms  the  posterior  abutments. 


Fig.  365. 


Fig.  366. 


Fig.  367. 


A  Spur  Support  consists  of  a  flange  formed  at  the  end  of  an 
extension  bridge,  affording  support  b}7  resting  on  the  palatal 
wall  of  either  an  incisor  or  a  cuspid,  or  in  the  sulcus  between  the 
cusps  of  a  bicuspid  or  molar,  as  shown  in  Fig.  368.  Fig.  369 
illustrates  a  case  with  a  spur  resting  against  a  cuspid.  In  the 
case  represented  in  Figs.  370  and  371  the  spur  rests  in  an  inden- 
tation in  an  amalgam  tilling  in  the  molar.  This  form  is  termed 
a  cantilever  bridge. 

In  extension  bridge-work,  the  portion  which  constitutes  the 
bridge  exerts  on  the  abutments,  in  resisting  the  force  of  occlusion, 
.an  action  like  that  of  a  lever.     The  ratio  of  the  force  exerted  is 


EXTENSION  BRIDGES. 


181 


proportioned  to  the  length  of  the  bridge  or  lever  from  the  abut- 
ment or  fulcrum.  This  principle  must  receive  consideration  in 
the  employment  of  this  form  of  bridge.  A  flange  or  spur 
support,  if  attainable,  should  as  a  rule  be  applied.     More  than 


Fig.  368. 


Fig.  369. 


one  tooth  should  not  be  extended  from  an  abutment  without 
ample  alveolar  support  besides.  "When  two  approximal  crowns 
support  an  extension  bridge  tooth  or  dummy,  the  force  is 
counterbalanced  by  the  resistance  of  the  farthest  anchorage 
crown  from  the  bridge,  the  pressure  on  which  is  in  a  direct  line 


Fig.  370. 


Fig.  371. 


from  the  socket,  the  approximal  crown  acting  as  a  fulcrum,  the 
force  on  which  is  upward  in  the  line  of  the  root.  The  occluding 
surfaces  of  the  bridge  teeth  should  be  made  unusually  narrow 
from  labial  to  palatal  side,  to  offer  less  occluding  surface  to  those 
antagonizing. 


CHAPTER    IV. 

BAR    BRIDGES. 

This  style  of  bridge  receives  its  name  from  the  fact  that  the 
teeth  or  dummies  forming  it  are  supported  by  bars  anchored 
in  the  natural  teeth  on  either  side  by  means  of  fillings.  Failure 
to  appreciate  its  limitations  and  faults  of  construction  are  re- 
sponsible for  disappointments  in  its  use  which  have  militated 
against  its  more  common  application. 

In  the  first  place,  its  successful  employment  is  confined  to  the 
insertion  of  one,  or  at  most  two  teeth.  An  attempt  to  support 
more  than  two  teeth  by  this  method  will  almost  certainly  result 
in  failure. 

The  most  glaring  fault  of  construction  is  insufficient  anchorage 
for  the  bars.  If  the  anchorage  tooth  is  alive,  the  bar  should  ex- 
tend in  a  suitably  shaped  cavity  two-thirds  or  three-fourths  the 

width   of  its   palatal  or  occluding   surface, 
Fig.  372.  ,.  .f  .  .      .  «j 

according  as  it  is  an  incisor  or  cuspid,  or 

/."'.  a  bicuspid  or  molar,  and  be  thoroughly  se- 

cured  by   the   filling-material.       Thus    an- 
chored, the  bar  is  capable  of  supporting  the 
J^T^f^tT^A  bridge  and  resisting  the  leverage  exerted  on 

/   L-:;;yv    W  -\  it  in  occlusion  and  mastication,  which  it  can- 

not reliably  do  when  simply  anchored  in  a 
shallow  filling  inserted  in  the  side  of  a  tooth, — an  incorrect 
method  too  often  practiced. 

In  a  pulpless  tooth  the  bar  should  be  bent  and  inserted  into 
the  root-canal,  as  shown  in  Fig.  372. 

In  the  incisors  and  cuspids  the  anchorage  cavities  or  slots  are 
formed  in  the  palatal  portion  of  the  teeth,  extending  from  the 
approximal  surface  contiguous  to  the  space  to  be  bridged,  two- 
thirds  to  three-fourths  the  width  of  the  tooth,  and  usually  about 
one-third  of  its  length  from  the  gingival  margin  (Fig.  373), 
direct  access  into  the  cavities  being  afforded  through  the  palatal 
182 


BAR  BRIDGES.  183 

wall.  The  slots  or  cavities  having  been  formed,  a  model  of  the 
case  is  made.  Should  the  cavities  to  receive  the  bar  be  imper- 
fectly represented  on  the  model,  they  should  be  trimmed  and 
shaped  to  correspond  to  those  in  the  mouth.  The  exact  align- 
ment of  the  porcelain  tooth  in  the  mouth  having  been  deter- 
mined with  the  aid  of  wax,  it  should  be  adjusted  on  the  model 
and  secured  in  position  by  a  matrix  of 
plaster. 

The  base  of  the  tooth  should  rest 
firmly  on  the  gum,  to  accomplish  which 
a  small  portion  of  the  plaster  should  be 
removed  from  underneath  the  tooth  on 
the  model. 

The  bar  is  best  constructed  of  iridio- 
platinum  wire,  14  to   16   gauge.     The 
wire  can  be  extended  in  one  piece  en- 
tirely across  the  bridge  from  one  anchor- 
age to  the  other  by  bending,  or  by  removing  a  portion  of  its 
bulk  back  of  the  porcelain  tooth;  or  the  bar  can  be  cut  and 
made  in  two  sections,  if  the  position  of  the  anchorage  cavities 
so  suggests. 

The  ends  of  the  bar  should  be  flattened  with  a  hammer, 
.annealed,  and  shaped  as  shown  at  A,  Fig.  373.  The  remainder 
of  the  section  of  the  bar  which  is  to  rest  in  the  cavity  is  best 
filed  on  the  sides,  so  as  to  give  it  a  somewhat  triangular  form, 
the  broad  base  of  which  is  toward  the  bottom  of  the  cavity. 
This  form  favors  the  ready  impaction  of  the  filling-material  which 
is  to  secure  the  bar. 

The  porcelain  tooth  having  been  backed,  the  bar,  whether  in 
one  piece  or  two  sections,  is  attached  to  it  with  wax  cement, 
then  removed  from  the  model  and  soldered.  Enough  gold  should 
be  added  to  properly  contour  the  tooth  and  securely  connect  the 
bar. 

Anchoring  the  Bur. — Gold  and  amalgam  are  the  only  filling- 
materials  suited  for  securing  bars.  Amalgam  is  objectionable 
only  when  the  position  of  the  cavity  renders  it  visible.  Under 
such  circumstances,  however,  the  exposed  portion  can  be  cut 
away  when  set.  and  covered  with  gold.     Fastening  one  end  of 


134  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

the  bar  temporarily  with  oxyphosphate,  while  the  other  is  being 
secured,  will  sometimes  facilitate  the  operation  of  anchoring  with 
amalgam.  When  the  anchorage  tooth  is  pulpless,  the  end  of  the 
bar  which  extends  into  the  canal  should  be  cemented  first.  Fre- 
quently when  bicuspids  and  molars  containing  large  cavities  of 
decay  are  used  for  anchorages,  it  is  advantageous  to  first  insert 
the  anchorage  fillings,  and  then  drill  out  sufficiently  to  admit  the 
bar,  which  can  then  be  secured  with  additional  filling-material. 

When  gold  is  the  filling-material  used,  the  rubber-dam,  which 
must  be  thin,  is  first  adjusted  on  the  natural  teeth,  and  the  bridge 
then  pressed  to  position  over  it.  In  anchoring  with  gold,  the 
best  way  is  to  first  fill  such  portions  of  the  cavities  as  are  inac- 
cessible when  the  bars  are  in  position,  how  far  to  proceed  being 
determined  by  occasionally  trying  in  the  piece  as  the  gold  is 
inserted.  The  bridge  is  then  pressed  to  place,  and  held  firmly 
while  the  ends  of  the  bars  are  secured  by  condensing  around 
them  a  few  pellets  of  foil,  after  which  the  gold  is  carefully  im- 
pacted around  the  bar,  the  filling  of  one  of  the  cavities  being 
carried  to  completion  before  going  on  with  the  other. 

In  the  preparation  of  the  cavities,  their  sides  should  be  given 
an  undercut  form  with  strong  edges.  When  only  sufficient 
tooth-structure  has  been  removed  at  the  approximal  portion  to 
just  admit  the  bar,  it  is  a  doubtful  expedient  to  attempt  to  fill 
the  narrow  seam  around  it  with  gold.  In  such  cases,  this  por- 
tion of  the  filling  is  better  made  with  amalgam,  which  is  inserted 
at  the  sides  and  along  the  floor  of  the  cavity  before  the  bridge 
is  fixed  in  position.  Then,  beginning  at  the  interior  end  of  the 
cavity,  gold  can  be  inserted  and  gradually  condensed  toward 
the  amalgam,  with  which  it  will  unite  when  brought  in  contact. 
Any  surplus  of  amalgam  can  be  removed  subsequently  when 
it  has  set.  Amalgam  placed  around  the  bar  as  here  described 
is  seldom  visible  from  the  labial  side,  and  the  quantity  required 
is  insufficient  to  materially  discolor  the  tooth. 

la  Bicuspid  and  Molar  Bar  Bridges  the  bar  should  be  carried  well 
across  the  occluding  surface,  and  the  end  bent  and  imbedded  in 
the  line  of  the  sulcus  toward  the  side  opposite  to  that  from  which 
the  bar  enters,  as  shown  in  Fig.  374.  Forming  the  end  of  the 
bar  in  this  way  affords  the  greatest  security,  when  it  is  properly 


BAR  BRIDGES. 


185 


Fig.  374. 


Fig.  375. 


anchored  with  the  filling-material,  by  preventing  any  rotatory 
movement,  or  any  loosening  of  the  bar  by  force  applied  in  a 
forward  direction. 

The  principles  involved  and  the 
method  described  for  shaping  and 
securing  the  ends  of  bars  apply 
equally  well  to  cases  where  one  end 
of  the  bridge  is  supported  by  a  bar 
and  the  other  by  an  artificial  crown , 
as  has  been  previously  illustrated. 

An  Extension  Bar  Bridge. — In  this  form  of  bridge  the  artificial 
(dummy)  tooth  is  supported  by  a  bar  anchored  in  a  natural 
tooth  at  one  end  only.  At  the  other  end  of  the  bridge  the  bar 
is  either  made  in  the  form  of  a  spur  to  rest  against  the  adjoining 
natural  tooth,  or  it  is  not  extended  beyond  the  dummy. 

In  the  case  represented  in  Fig.  375,  an  upper  cuspid,  the 
patient,  a  lady,  declined  to  have  the  bicuspid  capped  or  crowned 
in  any  way  for  the  purpose  of  sup- 
porting the  cuspid.  The  posterior 
approximal  side  of  the  bicuspid  at 
the  time  contained  a  large  filling. 
This  filling  was  removed,  and  a  cavity 
of  proper  shape  to  receive  a  bar  was 
extended  forward  from  it  between 
the  cusps  to  the  anterior  side.     A 

suitable  bar  for  the  cavity  was  formed  to  support  the  cuspid  in 
the  manner  illustrated  at  A  and  B.  The  angular  form  (C)  given 
the  bar  rendered  it,  when  anchored  with  the  filling-material,  very 
secure,  and  fully  capable  of  supporting  the  cuspid. 

The  filling-material,  which  was  gold,  occupied  most  of  the 
space  of  the  occluding  surface  between  the  cusps.  The  oc- 
cluding tooth  was  trimmed  off  proportionately.  A  spur  ex- 
tended from  the  anterior  side  of  the  artificial  tooth  resting  on 
the  lateral  incisor.  The  occlusion  was  favorable  to  the  insertion 
of  the  bridge  tooth  in  the  form  presented,  and  it  has  been  com- 
fortably and  satisfactorily  worn,  now  at  the  date  of  writing  four 
years.  When  recently  examined  it  showed  no  change,  except 
that  the  force  of  occlusion  on  the  cuspid  had  slightly  bent  the 


186  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

bar  and  caused  the  tooth  to  assume  a  deeper  position  in  the  jaw 
than  at  the  time  it  was  inserted,  though  this  was  only  to  the 
extent  of  the  absorption  of  gum-tissue  under  the  bridge.  In 
some  instances  the  bar  of  a  bridge  of  this  kind  can  be  extended 
across  the  occluding  surfaces  of  two  teeth,  and  additional  sup- 
port thus  obtained. 

Cast  Fillings,  as  described  on  page  139,  can  be  used  in  some 
instances  to  support  the  end  of  a  bar.  In  such  a  case,  a  short 
piece  of  wire  to  form  the  bar  is  inserted  in  position  in  the  wax 
in  the  matrix  of  platinum  before  it  is  removed  from  the  cavity, 
and  soldered  in  it.  The  attachment  of  the  bridge  is  then  made 
to  the  bar. 

Bar  bridge-work  affords  advantages  for  artificial  restoration, 
in  many  cases  where  a  single  tooth  has  been  lost,  not  presented 
by  other  methods.  Its  practical  success  depends  chiefly  upon 
the  character  of  its  supports  and  the  skillfulness  with  which  it  is 
anchored. 


CHAPTER    V. 

REMOVABLE  AND  REPLACEABLE  PORCELAIN  FRONTS. 

In  those  forms  of  crown-  and  bridge-work  in  which  porcelain 
fronts  are  used  there  is  some  liability  of  fracturing  the  fronts, 
either  in  the  soldering  processes  connected  with  its  construction, 
or  subsequently,  after  the  insertion  of  the  piece  in  the  mouth,  by 
the  patient  in  mastication.  The  replacing  of  a  porcelain  front 
after  the  work  has  been  permanently  fixed  in  position  is  fre- 
quently attended  with  great  difficulty,  and  the  result  is  often 
unsatisfactory  or  doubtful  regarding  its  permanency.  The  desire 
to  obviate  such  difficulties  has  prompted  the  introduction  of  vari- 
ous methods  of  construction  in  which  the  porcelain  fronts  are 
removed  from  their  positions  previous  to  the  soldering  processes, 
and  afterward  adjusted  so  as  to  be  easily  replaceable  by  means 
of  duplicates  in  case  of  fracture  when  the  work  is  being  worn 
in  the  mouth.  These  methods  applied  to  a  bar  bridge  afford 
access  to  the  cavities  of  anchorage. 

A  modification  of  Dr.  I.  F.  Wardwell's  method,  which  is 
simple  in  construction  and  application  in  comparison  with  most 
forms  in  use,  is  as  follows :  A  thick,  narrow  piece  of  18-carat 
gold  plate,  at  least  No.  18  standard  gauge,  is  soldered  to  the 
tooth,  and  its  two  sides  undercut  with  a  very  thin  separating  file 
(Figs.  376,  377).  A  very  thin  piece  of  platinum,  covering  the 
entire  back  of  the  tooth,  is  burnished  against  it,  well  into  the 
undercut  sides,  the  platinum  being  annealed  several  times  during 
the  operation.  The  platinum  is  held  in  a  flame  while  a  small 
quantity  of  pure  gold  is  flowed  over  the  outer  surface  and  then 
refitted  to  the  back  of  the  tooth,  to  which  it  is  again  burnished. 
This  operation  is  repeated  until  the  platinum  and  gold  form  a 
moderately  light  backing  which  fits  perfectly.  The  platinum  sur- 
face is  then  covered  with  investing  material,  and  on  the  other 
side  18-  or  20-caratgold  plate  flowed  until  a  suitable  thickness  is 
■obtained.     When  trimmed  into  proper  shape  and  attached  to  the 

187 


INS 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


bar,  this  forms  a  substantial  backing  or  socket  (Fig.  378),  in  which,- 
when  the  bar  is  anchored,  the  porcelain  tooth  can  be  fastened 
with  a  little  oxyphosphate  cement  or  gutta-percha  (Fig.  379). l 


Fig.  378. 


Fig.  379. 


Fig.  380. 


Any  ordinary  porcelain  front  to  a  bicuspid  or  molar  dummy 
can  be  made  on  the  removable  or  replaceable  plan,  by  backing 
the  porcelain  in  the  usual  manner  with  gold  or  platinum  plate 
without  bending  the  pins,  adjusting  the  gold  cap  in  position,  at- 
taching cap,  and  backing  with  wax  cement,  then,  removing  the 
porcelain  front  (Fig.  380),  investing  and  sol- 
dering the  cap  and  backing  together.  The 
backing  must  be  made  thick  with  solder,  the 
holes  in  it  deepened  with  a  drill,  and  the  pins 
of  the  porcelain  front  seriated  and  fitted  therein. 
After  the  final  soldering,  the  porcelain  fronts  are  cemented  in 
position  with  oxyphosphate. 

Dr.  Low  has  invented  for  use  in  crown-  or  bridge-work  a 
ready-made  metallic  socket  or  shell,  into  which  fits  a  correspond- 
ing porcelain  front,  which  can  be  replaced  in  case  of  fracture. 


Fig.  381. 


Fig.  382. 


Fig.  383. 


Fig.  384. 


Fig.  385. 


Fig.  381  shows  a  socket  shell ;  Fig.  382  the  same  with  por- 
celain in  position  ;  Fig.  383  a  socket  for  incisors  and  cuspids,  and 
Figs.  384  and  385  the  same  with  porcelain  in  position. 

1  Dr.  F.  T.  Van  Woert  has  introduced  a  pliers  with  combination  points  which 
simplify  the  construction  of  a  socket  of  this  form  and  the  replacement  of  the 
porcelain  front  in  case  of  its  fracture  by  the  patient. 


CHAPTER    VI. 

■GENERAL  APPLICATION  OF  CROWN-  AND  BRIDGE-WORK. 

The  construction  and  general  application  of  bridge-work,  as 
•explained  in  the  foregoing  chapters,  are  additionally  illustrated 
in  the  following  typical  cases  : 

Fig.  386. 


Fig. 


Figs.  386,  387,  388  represent  the  artificial  restoration  of  the 
four  superior  incisors  on  the  two  central  roots.  Spurs  might  be 
additionally  formed  on  the  laterals  to  rest  on  the  cuspids.  When 
approximal  crowns,  as  in  this  case,  are  united  to  support  bridge- 
work,  a  free  space  should  be  preserved  at  the  neck  between  their 
respective  collars  to  admit  the  gum  septum. 

189 


190 


ARTIFICIAL  CROWN-  AXD  BRIDGE-WORK. 


Figs.  389,  390,  391  show  a  bridge  of  the  incisors  supported 
by  two  collar  crowns  on  cuspid  roots.  Shell  crowns  can  also  be 
used  for  this  purpose,  according  to  the  preference  of  the  operator. 


Fig.  389. 


Fig.  390. 


lit 
Fig.  391. 


Figs.  392,  393  illustrate  a  method  of  replacing  a  superior  lat- 
eral. The  lateral  is  formed  with  a  base  of  gold  or  platinum 
resting  closely  on  the  gum.  A  gold  cap  crown  on  the  first  bi- 
cuspid supports  the  lateral  in  position  by  means  of  an  iridio- 
platinum  bar. 


GENERAL  APPLICATION  OF  CROWN-  AND  BRIDGE-WORK.    191 


Figs.  394,  395  represent  a  case  in  which  two  centrals  are  sup- 
ported in  position  by  bars  extending  from  gold  crowns  on  the 
right  and  left  first  bicuspids. 

Fig.  392.  Fig.  393. 


Fig.  396. 


Figs.  396,  397  show  bridge-work  supported  by  cuspid   and 
molar  crowns.     If  the  cuspid  contains  a  living  pulp,  the  natural 


192 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


crown  should  be  preserved,  and  a  shell  crown  used  iu  preference 
to  the  form  illustrated. 

Figs.  398,  399  illustrate  a  case  of  bridge-work  similar  to  the 
one  preceding  it,  extended  to  the  central  incisor.     Such  a  piece 


of  bridge-work  is  insured  against  misfit  from  warping  in  sol- 
dering during  its  construction  by  forming  it  in  sections.  The 
central  and  lateral  sections  can  be  made  separate  from  the  rest, 


Fig.  399. 


and  then  connected.     In  a  bridge  of  this  character,  if  the  cuspid 
is  intact,  a  shell  crown  is  preferable. 

Fig.  400  shows  the  form  of  bridge-work  suitable  for  the  re- 


EXTENSIVE  APPLICATIONS  OF  CROWN-  AND  BRIDGE-WORK.  193 


Fig.  400. 


Fig.  401. 


Fig.  402. 


placement  of  one  or  two  inferior  incisors.  The  labial  section 
of  the  shell  crowns  which  form  the  support  for  the  artificial 
tooth  should  be  removed  only 
sufficient  to  avoid  any  consider- 
ble  exposure  of  the  gold  in  the 
movement  of  the  lips. 

Fig.  401  explains  and  illus- 
trates a  method  of  restoring  an 
incisor  and  supporting  the  ad- 
joining loosened  teeth  with  suc- 
cessive cemented  collars  of  gold, 
in  cases  of  pyorrhea  alveolaris. 

Fig.  402  represents  a  case  fre- 
quently presented,  suitable  for 
bridge-work.  The  inclination 
of  the  teeth  toward  each  other 
suggests  the  construction  of  the 
bridge  in  the  form  illustrated. 
The  molar  is  capped  entirely, 
the  bicuspid  on  the  occluding 
surface,  with  the  gold  extend- 
ing down  on  the  contour  of  the 
natural    crown    (A)    only.      A 

pin  inserted  in  the  cap  fitting  a  hole  drilled  in  the  sulcus  of  the 
occluding  surface  will  secure  this  cap  in  position.  This  method 
is  very  suitable  to  a  case  where  the  crown  of  the  bicuspid  is  long 
and  the  root  slightly  exposed.  Molars  under  similar  circum- 
stances can  be  capped  for  bridge-work  in  like  manner. 

EXTENSIVE   APPLICATIONS  OF  CROWN-  AND  BRIDGE-WORK. 

The  following  illustrations  of  bridge-work  by  Dr.  H.  A.  Parr 
show  extreme  cases  in  the  way  of  large  operations  in  which  the 
system  has  been  applied. 

Figs.  403,  404,  405.  and  4(H)  represent  a  case  in  which  the 
roots  of  the  two  superior  centrals,  a  partially  decayed  right  first 
molar,  and  a  badly  decayed,  pulpless  left  first  molar  were  all  that 
remained  of  the  upper  natural  teeth.  On  the  two  central  roots 
were  mounted  collar  crowns,  and  on  the  two  molars  all-gold 

14 


194 


ARTIFICIAL   CROWN-   AND  BRIDGE-WORK. 


cap  crowns.     These  four  crowns,  acting  as  abutments  for  the 
bridge  denture,  bore  between  them,  proportionately   on    each 


Fig.  403 


Pig.  405. 


EXTENSIVE  APPLICATIONS  OF  CROWN-  AND  BRIDGE- WORK.  195 

Fig.  406. 


Fig   407. 


196 


ARTIFICIAL  CItOM'X-  AND  BRIDGE-WORK. 


side,  the  force  and  leverage  of  occlusion.  The  contour  of  the 
arch  in  the  region  of  the  cuspids  was  restored  by  a  skillful 
and  artistic  placing  of  the  artificial  teeth,  which  are  prominent 
and  long. 

Figs.  407,  408,  409,  and  410  represent  a  case  in  which  two 
large  and  firm  superior  cuspid  roots,  and  a  right  pulpless  molar, 
with  a  saddle — an  invention  of  Dr.  Parr's — on  the  left  side  sup- 
port a  large  bridge. 

Fig.  409. 


Fig.  410. 


In  the  bridge-work  illustrated  in  Figs.  411,  412,  and  413, 
crowns  on  a  second  bicuspid,  a  pulpless  molar,  and  the  roots  of  a 
cuspid  and  lateral  constitute  the  abutments. 

Fio-s.  414  and  415  illustrate  an  extensive  case  of  artificial 
replacement  by  crowning  and  bridging  operations.  Fig.  414 
represents  the  case  as  presented  for  treatment.  The  few 
remaining  superior  and  inferior  natural  teeth  had  no  corre- 
sponding antagonists,  which  caused  the  interlocking  and  abnor- 
mal condition  in  regard  to  occlusion  shown.  The  superior 
right  bicuspid,  the  left  central,  and  the  left  cuspid  were  crowned, 
the  bicuspid  being  shortened  and  the  cuspid  lengthened  in  the 


EXTENSIVE  APPLICATIONS  OF  CROWN-  AND  BRIDGE-WORK.  197 

Fig.  411. 


Fig.  412. 


Fig.  413. 


198 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


operation.  The  intervening  lateral  root  between  the  central 
and  cuspid,  having  been  treated  and  rilled,  was  allowed  to 
remain.  With  the  three  crowns  to  serve  as  abutments  the 
intervening  spaces  were  bridged  with  artificial  teeth,  the  exten- 


Fig.  414. 


Fig.  415. 


sion  on  the  left  side  being  supported  by  a  saddle.  The  spaces 
between  the  inferior  cuspids  and  molars  on  both  sides  were 
bridged,  the  bicuspid  on  the  left  supporting  the  bridge,  instead 
of  the  cuspid,  as  on  the  right ;  the  left  cuspid  was  crowned  and 
the  incisive  edsjes  of  the  incisors  trimmed  even. 


EXTENSIVE  APPLICATIONS  OF  CROWN-  AND  BRIDGE-WORK.  199 

Fig.  415  illustrates  the  case  finished,  and  shows  the  complete 
artificial  restoration  of  the  parts. 

In  the  case  illustrated  by  Figs.  416  and  417.  two  superior  mo- 
lars and  a  second  bicuspid  on  the  right,  and  a  first  bicuspid  and 

Fig.  416. 


a  saddle  under  the  "  dummy"  representing  the  first  molar  on 
the  left  side,  form  the  abutments.  Prior  to  the  insertion  of  the 
bridge-work,  the  patient  had  worn  artificial  teeth  on  a  plate. 


Fig.  417. 


Figs.  418  and. 419  represent  a  case  in  which  crown-  and  bridge- 
work  has  been  extensively  applied.  The  occluding  surfaces  of 
the  teeth  were  affected  with  abrasion.  Gold  crowns  with  porce- 
lain fronts  which  presented  laterally  the  form  illustrated  were 
mounted  on  the  incisors  and  cuspids,  the  pulps  of  which  were 


200  ARTIFICIAL  CROWN- AND  BRIDGE-WORK. 

Fig.  418. 


Fig.  419. 


EXTENSIVE  APPLICATIONS  OF  CROWN-  AND  BRIDGE-WORK.    201 

preserved.  The  posterior  teeth  were  crowned  with  all-gold 
crowns.  The  missing  teeth,  except  those  on  the  inferior  left 
side,  were  artificially  restored  with  bridge-work. 

The  application  of  cemented  bridge-work  of  the  extensive 
character  illustrated  in  some  of  these  cases  is  seldom  practiced 
now.  Removable  plate  bridges,  which  offer  the  additional  ad- 
vantage of  alveolar  support,  are  used  in  preference.  Cemented 
bridge-work  in  sections  is  still  used,  and  extended  around  the 
arch,  where  the  abutments  are  numerous  and  offer  suitable  sup- 
ports. 


CHAPTER    VII. 


REPAIR  OF  CROWN-  OR  BRIDGE-WORK. 


Fig.  420. 


The  fracture  of  a  porcelain  front  to  a  permanently  attached 
bridge  is  an  annoying  incident  for  both  patient  and  dentist.  It 
is  usually  attributable  to  failure  to  properly  protect  the  incisive 
edge  or  occluding  surface  of  the  porcelain  with  metal,  a  precau- 
tion rendered  necessary  by  the  rigid  character  of  the  resistance 
offered  the  antagonizing  teeth  through  the  abutments.  In  most 
cases  the  porcelain  can  be  replaced  without  the  removal  of  the 
bridge,  but  the  attachment  is  not  usually  so  reliable  as  in  the 

original  piece.  The  following  is  the 
method  commonly  adopted  with 
incisors  or  cuspids:  The  surface 
of  the  backing  to  the  porcelain  is 
trimmed  level,  the  platinum  pins 
drilled  out,  and  the  holes  slightly 
countersunk  on  the  palatal  side. 
A  tooth  similar  to  the  one  frac- 
tured, with  long  pins,  is  ground 
and  fitted  to  the  backing.  If  a 
suitable  long-pin  tooth  is  not  pro- 
curable, the  short  pins  of  an  or- 
dinary tooth  can  be  lengthened  by 
bending  a  piece  of  platinum  wire  in  the  form  of  a  semicircle, 
and  soldering  its  ends  to  the  ends  of  the  pins  with  pure  gold. 
The  wire  is  then  cut  in  the  center,  and  the  lengthened  pins 
trimmed  as  required.  The  pins  are  then  riveted  on  the  palatal 
side  into  the  countersunk  holes  of  the  backing.  The  riveting 
is  best  done  with  punch  forceps  having  a  large  punch,  the  por- 
celain front  being  protected  by  a  piece  of  lead  placed  against  the 
labial  aspect  (Fig.  420).     The  heads  of  the  pins  should  then  be 

202 


REPAIR  OF  CROWN-  OR  BRIDGE-WORK.  203 

burnished  smooth  with  a  revolving  burnisher.  In  case  of  the 
fracture  of  the  porcelain  front  of  a  bicuspid  crown  or  dummy, 
a  corresponding  front  is  selected  with  very  long  pins,  and  ground 
to  lit.  Holes  are  drilled  in  the  gold,  in  proper  positions,  to  re- 
ceive the  pins  their  full  length.  The  pins  are  then  roughened 
a  little  with  a  sharp  instrument,  and  pins  and  front  are  cemented 
to  the  gold.  Should  the  holes  extend  through  the  gold  at  the 
palatal  side,  the  cement  and  the  ends  of  the  pins  should  be 
covered  with  gold  foil  or  amalgam.  If  any  gold  is  present  to 
protect  the  occluding  edge  of  the  porcelain,  it  should  be  bur- 
nished against  the  surface. 

Another  method  to  replace  a  porcelain  front  is  the  following : 
Back  the  porcelain  front  around  the  pins  with  platinum  foil, 
bend  the  pins  down  together  on  the  platinum,  andhammerthem 
flat.  Invest  and  flow  a  little  gold  plate  over  the  pins  and  platinum, 
and  file  the  metal  down  close  to  the  porcelain.  Drill  a  hole  in 
a  strong  part  of  the  backing  on  the  bridge  at  a  central  point, 
square  the  hole,  and  fit  to  it  a  piece  of  square  platinum  wire. 
Attach  the  end  of  the  wire  to  the  backing  of  the  porcelain  front 
with  an  atom  of  wax  cement,  and  while  warm  insert  the  wire 
through  the  hole  in  the  backing  on  the  bridge,  and  adjust  the 
porcelain  front  in  correct  position.  Chill,  and  remove  front  and 
wire.  Invest,  and  solder  wire  to  backing  on  porcelain  front 
with  18-carat  gold  solder,  and  then  remove  all  metal  from  back 
-of  porcelain,  except  what  is  necessary  to  secure  the  end  of  the 
wire  to  the  pins.  Countersink  the  gold  backing  on  bridge 
sufficient  to  permit  the  front  to  come  in  position.  Slit  the  end 
■of  the  wire,  cement  the  porcelain  front  in  position  to  the  back- 
ing, and  bend  the  ends  outward  into  two  slightly  grooved  places 
on  the  1  »acking.  Fill  the  slit  in  the  wire  with  gold,  and  smooth 
the  surface.1 

Dr.  R.  AV.  Starr's  method  differs  from  the  preceding,  in  that 
he  uses  round  instead  of  square  wire,  cuts  the  pins  of  the  por- 
celain front  off  short,  making  corresponding  depressions  in  the 
backing  on  the  bridge  to  receive  them  and  prevent  rotation,  and 
solders  the  end  of  the  wire  to  retain  the  front  between  the  pins. 

1  Dr.  W.  W.  Williamson's  method. 


204  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

He  then  cuts  a  screw  thread  on  the  wire,  and  secures  it  in  the' 
backing  with  a  nut  on  the  palatal  side  screwed  into  a  depression 
reamed  to  receive  it.     Figs.  421,  422,  423,  and  424  illustrate  this 
method. 

Fig.  421.  Fig.  4-22.  Fig.  423.  Fig.  424. 


Bridge-work  can  be  made  with  replaceable  porcelain  fronts 
which  can  be  easily  substituted  in  case  of  fracture.  A  descrip- 
tion of  their  application  will  be  found  at  page  188. 

If  the  character  of  the  breakage  is  such  as  will  not  permit  its 
repair  in  the  mouth,  the  bridge  must  be  removed  for  the  pur- 
pose and  then  reinserted.  Under  such  circumstances  the  advan- 
tages of  bridge-work  in  a  detachable  form  are  most  evident. 

The  results  following  the  repair  of  single  crowns  in  the  mouth 
will  seldom  repay  the  labor  attending  it. 

Removal  of  Cemented  Orowns  "nil  Bridges. — When  it  becomes 
necessary  to  remove  an  artificial  crown,  whether  inserted  singly 
or  as  a  support  for  a  bridge,  incisors  or  cuspids  are  detached  by 
grinding  the  gold  or  porcelain  away  at  the  palatal  section  over 
the  post,  which  when  exposed  is  severed,  and  the  attachment  of 
the  cement  broken  up.  The  collar  can  also  be  slit  and  bent 
aside  if  found  necessary.  In  an  all-gold  cap  crown  on  a  posterior 
tooth  a  hole  drilled  in  the  grinding-surface  will  give  access  to  the 
cement,  a  sufficient  quantity  of  which  can  then  be  removed  to 
loosen  the  attachment ;  or,  the  collar  can  be  divided  and  pried 
up  from  the  root  by  first  making  a  groove  with  a  small  rubber 
and  corundum  disk,  and  then  cutting  the  gold  with  a  sharp  in- 
strument. With  care  and  patience  in  the  operation,  the  crowns 
will  not  usually  be  injured  beyond  repair. 

When  gutta-percha  is  the  cement  that  has  been  used,  a  hot 
instrument  can  be  placed  against  the  metallic  part  of  the  crown, 
or  the  crown  seized  with  the  beaks  of  heated  forceps,  the  gutta- 
percha thereby  softened,  and  the  crown  removed. 

A  hole  or  slit  in  a  gold  collar  or  crown  is  repaired  easily  by 


REPAIR  OF  CROWN-  OR  BRIDGE-WORK.  205 

first  placing  a  piece  of  soft  wax  in  the  hole  or  slit  on  (he  outside 
°f  M'e  gold,  adapting  a  piece  of  platinum  foil  larger  than  the 
aperture  on  the  inside  close  against  the  gold,  and  fixing  it  to  the 
wax.  The  interior  of  the  crown  is  next  filled  with  investing 
material,  and  solder  flowed  over  the  platinum  and  gold  on  the 
outside  of  the  collar  or  crown.  The  crown  should  be  heated 
slowly,  to  allow  the  plaster  to  dry  out  before  the  soldering  is 
.begun. 


CHAPTER    VIII. 

THE  HYGIENIC  CONDITION   OF  THE   MOUTH  AS  AFFECTED  BY 

BRIDGE-WORK. 

The  probable  future  condition  of  a  mouth  in  which  a  piece 
of  bridge-work  is  permanently  fixed  is  a  matter  of  the  deepest 
interest  to  both  patient  and  operator.  There  is  no  valid  reason 
why  an  artificial  structure  in  the  mouth  should  be  more  hurtful 
than  that  which  is  natural,  provided  that  correct  conditions  are 
observed  in  its  construction  and  proper  measures  are  taken  for 
their  maintenance.  The  natural  teeth  demand  care  on  the  part 
of  their  owners,  and  all  forms  of  artificial  dentures  require 
attention  to  secure  their  cleanliness  and  thus  preserve  the  health 
of  the  adjacent  tissues.  What  will  result  from  the  wearing  of 
a  permanently  fixed  bridge  is  almost  wholly  dependent,  in  the 
first  place,  on  the  proper  application  of  principles  and  correct 
formation  in  every  detail  of  construction  of  both  crowns  and 
bridge-work ;  and  in  the  second  place,  upon  the  maintenance  of 
cleanliness.  Xeglect  of  a  single  requirement  will  so  far  detract 
from  the  usefulness  of  the  work,  and  may  influence  the  final 
result  disastrously. 

Firm,  properly  selected  abutments  will  not  redeem  incorrect 
conception  or  faulty  construction  ;  neither  will  the  best  construc- 
tion remedy  that  which  is  wrong  in  principle  or  application. 
Self-cleansing  spaces,  if  improperly  formed,  have  exactly  the 
contrary  effect  from  what  is  intended,  by  becoming  receptacles 
for  particles  of  food  debris,  instead  of  preventing  their  accumu- 
lation. 

Inaccessible  spaces  or  interstices,  which  are  always  apt  to  cause 
uncleanliness,  should  be  avoided.  Continuity  of  structure  of  the 
several  parts  is  also  essential  to  fully  insure  perfect  hygienic 
conditions. 

The  health  of  a  mouth  containing  a  piece  of  bridge-work 

206 


THE  HYGIENIC  CONDITION  OF  THE  MOUTH.  207 

constructed  under  these  precautions  can  be  readily  maintained. 
For  this  purpose  a  suitably  funned  brush  and  a  dentifrice  are 
necessary.  FJoss  silk  can  be  passed  through  apertures  around 
the  necks  of  crowns,  in  places  out  of  reach  of  the  brush,  and 
drawn  along  the  gum  under  the  bridge  by  the  aid  of  a  slightly 
curved  blunt-pointed  needle,  to  remove  accumulations  of  debris 
otherwise  inaccessible.  A  solution  of  a  detergent  and  disin- 
fectant mouth  lotion  in  water,  injected  with  a  dental  syringe, 
can  be  used  advantageously  to  wash  out  such  places  and  maintain 
a  healthy  condition  of  the  gums.  In  addition  to  these  measures, 
the  crown  and  bridge  should  be  thoroughly  cleansed  by  the 
dentist  at  regular  intervals. 

So  cared  for,  a  permanently  fixed  bridge  will  not  militate 
against  the  absolute  wholesomeness  of  the  mouth ;  but  it  can 
hardly  be  expected  that  the  insertion  of  bridge-work  will  insure 
a  state  of  the  mouth  which  for  cleanliness  will  be  superior  to  the 
presence  of  the  natural  teeth.  iSTeglect  on  the  part  of  the  patient 
to  perform  such  duties  as  are  necessary  to  preserve  the  natural 
teeth  in  a  healthy  state  will  have  about  the  same  effect  on  an 
artificial  denture.  The  attention  required  to  be  given  to  bridge- 
work  is  not  greater  than  is  commensurate  with  the  advantages 
which  it  confers  on  the  wearer. 


CHAPTER   IX. 

KEMOVABLE    AND   DETACHABLE    BRIDGE-WORK. 

The  evident  advantages  of  bridge-work  have  stimulated  the 
inventive  genius  of  dental  mechanists  to  improve  the  methods 
and  forms  of  its  construction  and  to  extend  its  application. 
With  these  objects  in  view,  some  bridges  have  been  made  so  as 
to  be  easily  detachable  by  the  dentist,  and  others  removable  by 
the  patients  themselves. 

The  construction  of  bridge-work  in  either  of  these  forms 
overcomes  the  chief  objections  to  the  system.  Large  bridges 
are  much  more  easily  made  in  a  detachable  or  removable  form 
than  are  the  smaller  pieces,  which  present  some  of  the  best 
features  of  the  permanently  attached  methods. 

In  all  kinds  of  removable  bridge-work  a  prime  requisite  is 
that  the  posts  and  collars,  or  other  form  of  attachment  used, 
shall  be  so  constructed  that  the  piece  shall  move  evenly  on  or  off 
the  supporting  roots  or  crowns  in  adjustment  and  removal.  To 
secure  this,  the  post- cavities  and  the  gold  crowns  should  be  so 
shaped  that  the  lines  of  the  cavities  and  of  the  sides  of  the  gold 
crowns  shall  be  as  nearly  as  possible  parallel  to  one  another. 
To  facilitate  this,  a  post  of  wood  or  metal  may  be  first  accu- 
rately but  loosely  inserted  in  any  root-canal  intended  to  receive 
a  post,  and  left  protruding  a  quarter  of  an  inch,  and  an  impres- 
sion taken.  On  the  model  made  from  this  impression  the  post 
will  be  found  placed  as  in  the  mouth.  The  position  and  shape 
of  the  natural  teeth  or  roots  can  be  thus  studied,  and  their  plas- 
ter forms  trimmed  as  a  guide.  Gutta-percha  or  impression 
compound,  fitted  to  the  model  and  removed  with  the  posts  in 
position  in  it,  can  then  be  used  to  guide  the  operator  and  gauge 
the  preparation  of  teeth  or  roots  in  the  mouth.  Posts,  or  the 
tubes  inclosing  them,  should  be  placed  as  nearly  as  possible  in 
208 


REMOVABLE  INCISOR  OR  CUSPID  CROWN. 


209 


the  lines  of  the  root-canals  to  avoid  weakening  the  side  or  sides 
of  the  root. 

When  a  molar  leans  forward,  the  removal  of  a  portion  of  the 
anterior  approximal  side  usually  restores  its  perpendicularity 
sufficiently,  as  does  the  cutting  away  of  the  posterior  side  of  a 
bicuspid  which  inclines  backward. 

The  methods  and  forms  of  attachments  most  commonly  used 
in  the  different  styles  of  removable  bridge  dentures  are  very 
similar.  A  preliminary  description  of  these  and  of  their  con- 
structive details  is  therefore  first  in  order. 


Fig.  425. 


Fig.  426. 


; 


REMOVABLE    INCISOR    OR    CUSPID    CROWN. 

A  removable  gold  crown  with  a  porcelain  front  is  frequently 
used  in  connection  with  removable  bridge-work  where  incisors 
or  cuspids  form  abutments.  The  cap  and  tube  crown  is  the 
style  (Fig.  425)  preferably  applied.  It  consists  of  a  cap  for  the 
end  of  the  root  with  a  tube  attached  ex- 
tending up  the  root-canal,  and  on  the  cap 
the  crown  with  a  post  fitted  tightly  to  the 
tube  is  adjusted.  To  the  crown  so  formed 
(Fig.  426)  the  bridge  is  joined  in  the  usual 
manner.  The  end  of  the  post  can  be 
formed  with  a  slit  which  will  permit  this 
portion  to  be  slightly  expanded,  making 
what  is  termed  a  spring-post.  The  con- 
structive details  of  this  crown  are  as  fol- 
lows :  The  root  is  first  prepared  and  capped 
the  same  as  for  a  collar  crown.  The  collar 
can  be  formed  of  gold  and  the  cap  section  of 
platinum,  No.  32  gauge  (A,  Fig.  427).  A 
substantial  piece  of  gold  and  platinum  wire,  from  Xo.  16  to  Xo. 
18  gauge  (the  number  being  regulated  by  the  size  of  the  root),  is 
slit  for  about  one-eighth  of  an  inch  to  form  a  spring-post.  This 
is  easily  done  by  placing  the  wire  in  a  vise  and  steadily  cutting 
it  downward  from  one  end  through  the  center  to  the  required 
depth  with  a  saw-edged  strip  of  very  thin  steel  (Fig.  428).  This 
takes  only  a  tew  minutes,  and  is  preferable  to  the  method  some- 
times adopted  of  partially  joining  two  pieces  of  half-round  wire. 

15 


J 


210 


ARTIFICIAL  CROWN-  ASD  BRIDGE-  W< )RK. 


The  wire  is  theD  tapped  together  at  the  slit,  burnished  smo<  >th 
and  rounded  just  at  the  end  (B,  Fig.  4-27).  The  tube  for  this 
post  is  formed  by  once  encircling  the  post  with  a  piece  of  iridio- 
platinum  plate,  No.  34  gauge,  the  edge  of  which  is  beveled  and 
cut  to  meet  the  plate  even  and  close  (C).  The  post  is  then 
withdrawn,  and  the  seam  is  touched  along  its  length  with  the 
smallest  possible  quantity  of  borax.  The  proper  way  to  use 
borax  in  tine  work  is  to  grind  it,  mixed  with  water,  on  a  slab, 
to  a  cream-like  consistence,  and  apply  on  the  point  of  a  camel's- 
hair  brush.  A  very  small  piece  of  pure  gold  is  placed  in  the 
seam,  and  the  tube  is  held  in  a  Bunsen  flame.  When  a  suffi- 
cient degree  of  heat  is  reached,  the  gold  will  flow  along  the 
seam  and  form  a  joint  without   obstructing  the  inside   passage 


Fig.  428. 


Fig.  429. 


for  the  post.  The  post  is  then  inserted,  and  the  tube  trimmed 
(D),  and  gauged  in  a  gauge-plate.  With  a  drill  just  the  size 
of  the  tube  the  root-canal  is  enlarged  so  that  the  tube  will  fit 
tightly  (Fig.  429).  This  plan  prevents  weakening  of  the  root  by 
too  great  enlargement  of  the  canal.  A  hole  the  size  of  the  tube 
is  made  through  the  cap,  and  cap  and  tube  are  then  adjusted, 
waxed  together,  and,  the  post  being  withdrawn,  they  are  removed, 
invested,  with  the  investing  material  inserted  in  the  tube,  and 
soldered.  The  second  or  outer  cap  is  then  constructed  for  the 
root-cap,  of  a  piece  of  platinum  about  No.  34  gauge.  It  is  per- 
forated in  the  center,  and  the  post  fitted  in  proper  position.  At  the 
palatal  and  approximal  sides,  if  desirable,  the  platinum  can  be  slit 
and  bent  over  the  edge  of  the  root-cap  to  form  an  inner  par- 
tial band  or  flange,  or  a  half  band  can  be  formed  of  a  piece  of 


REMOVABLE  IX  CI  SOU  OR  CUSPID  CROWN. 


211 


plate,  the  open  space  at  the  labial  side  being  filled  with  the  por- 
celain tooth.  The  outer  cap  and  the  post,  having  been  cemented 
with  wax,  are  removed  and  soldered  together.  As  the  point  of 
the  post  may  have  to  be  tiled,  it  is  well  to  place  it  so  that  the  line 
of  the  slit  shall  cross  the  tooth  from  mesial  to  distal  side.  On 
this  outer  cap  the  porcelain  front  is  fitted  and  soldered.  The 
end  of  the  tube  is  closed  with  a  little  gutta-percha,  and  the  root- 
cap  cemented  on  the  root  with  oxyphosphate  and  the  crown 
placed  on  it,  which  helps  to  bring  the  root-cap  to  its  place  and 
insure  the  intended  position  of  the  crown.  When  necessary, 
the  split  post  can  be  tightened  in  the  tube  by  slightly  springing 
it  open.  Fig.  426  represents  the  finished  crown.  The  incisive 
edge  of  the  porcelain  does  not  necessarily  require  to  be  protected 
with  metal  as  in  fixed  bridge-work. 

Fig.  430  illustrates  a  removable  cuspid  crown  which  can  be 
used  in  removable  bridge-work.  It  is  constructed  as  follows  : 
The  end  of  the  root  is  first  capped,  and  a  post  attached  fitting 
the  root-canal.  A  porcelain  cross-pin  tooth,  the  pins  of  which  are 
set  well  apart,  is  then  ground  and  adjusted  in  position,  cemented 
with  wax  to  the  cap,  and  both  removed.  Enough  plaster  to 
form  a  matrix  is  placed  on  the  labial  aspect  of  the 
porcelain  and  collar  to  hold  them  in  relative  position 
when  the  wax  is  removed.  A  flat  p<  >st  is  then  formed 
on  the  root-cap,  extending  from  the  palatal  edge  for- 
ward between  the  pins  of  the  tooth,  the  porcelain  of 
which,  between  the  pins,  should  be  slightly  cut  out 
to  receive  it.  To  this  is  soldered  the  piece  A,  which 
is  to  act  as  a  spring.  .The  post  is  formed  of  gold 
plate  Xo.  18  gauge,  and  the  spring  of  clasp  or  spring 
gold  Xo.  26.  The  post  is  soldered  to  the  cap  from 
the  opposite  side  to  the  spring  by  investing  without 
the  tooth.  The  tooth  is  then  lined  with  very  thin 
platinum,  and  with  the  aid  of  the  matrix  is  adjusted 
in  position  on  the  cap,  and  a  thin  piece  of  platinum 
plate  is  slit  at  the  edge-  and  adapted  over  the  post. 
cap,  and  edge  of  the  collar,  with  its  inner  edge  meet- 
ing the  backing  of  the  tooth.  The  platinum  plate  is  then 
cemented    with   wax    to    the    backing    on    the    tooth,    removed 


Fig.  430. 


212  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

with  it  from  the  cap  and  post,  and  invested,  the  slot  for  the  post 
being  carefully  filled  with  the  investing  material.  Twenty- 
carat  gold  solder  is  then  flowed  over  the  plate  and  backing  so  as 
to  consolidate  the  parts  in  one  piece. 

This  crown  when  finished  will  fit  on  to  the  cap  and  post,  the 
spring  of  which  can  be  bent  to  securely  retain  it.  The  line  of 
the  post  on  the  cap  as  it  fits  in  the  slot  in  the  crown  should  be 
such  as  will  favor  the  insertion  and  removal  of  the  bridge.1 

In  the  form  shown  in  Fig.  431,  which  is  a  sectional  view,  a 
square  or  round  iridio-platinum  wire  is  used  as  a  post  on  the 
cap  instead  of  the  form  above  described. 

The  post  having  been  soldered  to  the  cap,  a  thin  piece  of  plat- 
inum is  first  perforated  and  fitted  over  the  top  of 
Fig.  431.      ^\q,  cap,  next  a  tube  of  platinum  over  the  post  and 
#\        between  the  pins  of  the  porcelain.     The  porcelain 
JEM       front  is  then  lined  with  platinum  foil,  and  cemented 
^  VJ      with  wax  to  the  tube  and  the  platinum  at  the  base, 
and   removed   and  soldered  together.     "Where    one 
/^W^k      end  of  a  bridge  is  securely  attached  to  a  molar,  the 
form  of  crown  here  described  is  ample  support  for 
the  other  end. 

REMOVABLE    BICUSPID    AND    MOLAR   ATTACHMENTS. 

Bicuspids  and  molars,  especially  the  latter,  in  all  cases  where 
possible,  are  the  teeth  selected  and  most  depended  on  to  support 
all  forms  of  removable  bridge-work. 

Removable  Partial  Cap  and  Collar. — This  is  a  form  of  attach- 
ment made  to  fit  over  a  natural  tooth,  or  more  frequently  a  gold 
crown. 

The  sides  of  the  natural  tooth  have  to  be  first  trimmed  as 
nearly  as  possible  straight  or  parallel  to  the  sides  of  any  other 
supporting  crown  or  line  of  attachment.  If  the  tooth  is  to  be 
first  capped,  a  straight-sided  gold  crown  is  made  and  fitted.  The 
gold  crown  is  then  removed,  a  strip  of  damp  paper  wound  around 
it,  and  fusible  metal  melted  and  poured  in  crown  and  paper  tube. 
This  forms  a  die  of  the  crown,  with  a  shank  as  seen  in  Fig.  432. 
When  the  natural  tooth  is  not  crowned  with  gold,  a  die  of  the 

1  Dr.  Parr's  method. 


REMOVABLE  BICUSPID  AND  MOLAR  ATTACHMENTS.       213 


tooth  is  made  in  a  manner  similar  to  that  described  on  page  105, 
and  in  chapter  on  Molds  and  Dies.  The  crown  is  then  en- 
circled with  a  strip  of  pure  gold  about  30  gauge,  one  part  of 
which  will  extend  above  the  rest  in  the  form  shown  in  Fig.  433. 
The  sections  of  the  gold  at  A,  A  are  to  reach  from  the  edge 
of  the  neck  of  the  crown  to  or  slightly  above  the  occluding  sur- 
face.     The  gold  is  fitted  evenly,  but  not  tightly,  around  the 


Fig.  432. 


Fig.  433. 


A 


A 


crown,  the  ends  being  placed  at  the  side  opposite  to  that  where 
the  collar  will  be  joined  to  the  bridge  if  the  space  permits.  The 
collar  is  then  removed  and  the  ends  soldered  together  (Fig.  434). 
The  collar  is  readjusted  on  the  crown,  and  the  part  at  B,  Figs. 
434  and  436,  bent  down  over  the  occluding  surface,  so  that  it 
nearly  meets  the  collar  section  A.  On  the  outside  of  the  collar 
a  slightly  narrower  strip  of  gold  clasp  plate,  JSo.  30  (Fig.  435), 

Fig.  435.  Fig.  436.  Fig.  437.  Fio.  438. 


is  next  adjusted  in  the  position  shown  by  the  lines  C,  Fig.  435, 
then  removed  and  the  ends,  which  are  best  placed  at  the  point 
C,  Figs.  435  and  436,  soldered  together.  It  is  readjusted  on  the 
gold  collar,  removed  with  it,  and  soldered  to  it.  The  collar  can 
be  invested  for  this  purpose,  but  the  work  is  more  easily  done 
by  holding  the  collar  in  a  Bunsen  flame  and  placing  small  pieces 
of  solder  in  position  in  the  seam.     Only  enough  solder  should 


214  - 1  R  TIFJt  V.  I  L  ( 'RO  WN-  AND  BRIDGE-  WORK. 

be  used  to  unite  the  parts,  any  surplus  being  carefully  avoided. 
Painting  the  inner  surface  of  the  collar  with  whiting  will  pre- 
vent the  solder  flowing  there. 

The  collar  section  of  the  removable  cap  is  then  trimmed  smooth. 
The  cap  section  at  B  can  be  adjusted  and  soldered  to  the  collar 
now,  or  preferably  after  the  cap  has  been  united  to  the  bridge, 
and  its  relative  position  on  the  gold  crown  accurately  determined. 
Fig.  437  shows  the  gold  crown  and  the  finished  removable  par- 
tial gold  cap  over  it. 

The  gold  crown  is  freed  from  the  fusible  metal  by  dropping 
it  with  the  die  into  a  ladle  containing  a  quantity  of  melted  fusible 
metal.  The  portion  within  the  crown  will  melt  in  with  that  in 
the  ladle  and  leave  the  crown,  which  should  then  be  removed 
and  immersed  in  nitric  acid  to  remove  any  traces  of  the  fusible 
metal  still  adhering  to  the  gold. 

Flanged  Collar  Attachment. — Fig.  438  shows  another  form  of 
removable  partial  cap.  In  this  the  entire  edge  of  the  collar  is 
bent  over  on  the  occluding  surface  of  the  crown,  and  thereby 
supported  in  position.  In  the  construction  the  edge  of  the  pure 
gold  collar  should  be  shaped  to  form  the  flange. 

Spur  Collar  Support. — Fig.  439  illustrates  a  form  in  which  a 
straight-sided  removable  collar  is  maintained  in  position  by  a 
lug  or  spur  on  the  side  of  a  gold  crown. 

Removable  Partial  Cap  and  Clasp  Attachment. — In  this  form  a 
partial  cap  in  combination  with  an  elastic  gold  clasp,  encircling 
only  a  portipn  of  the  crown,  is  used  instead  of  a  collar.  Its 
application  is  principally  confined  to  a  cuspid  or  bicuspid  tooth 
or  artificial  crown. 

The  attachment  is  best  constructed  on  a  metallic  die,  either 
of  the  natural  tooth  or  of  the  artificial  crown  mounted  on  a 
model.  In  the  case  of  a  cuspid  a  piece  of  pure  gold,  Xo.  31 
gauge,  is  adapted  to  the  palatal  surface  and  partly  over  on  the 
approximal  side,  in  the  form  shown  at  A,  Fig.  440.  In  some 
cases  it  may  be  extended  to  the  incisive  edge.  A  gold  clasp  of 
at  least  24  gauge  is  fitted  over  the  gold  partial  cap  in  the  position 
shown  in  Fig.  441,  the  cap  being  beveled  to  an  imperceptible 
edge  on  the  sides  at  the  points  where  the  clasp  passes  forward, 
to  assure  perfect  adaptation.     Cap  and  clasp  are  next  cemented 


REMOVABLE  BICUSPID  AND  MOLAR  ATTACHMENTS. 


215 


with  wax,  then  removed  and  joined  at  the  approximal  sides 
with  a  very  small  quantity  of  solder.  The  attachment  is  then 
ready  to  be  connected  to  the  bridge,  denture,  which  should  be 
done  by  soldering  the  clasp  portion  only  at  the  point  B,  Fig.  441. 
This  method  allows  the  soft  gold  of  the  cap  portion  to  be  again 
adapted  to  suit  any  position  the  clasp  may  assume  in  the  final 
adjustment  of  the  denture  in  the  mouth.  The  bridge  and  clasp 
should  then  be  again  invested,  and  solder  flowed  over  and  be- 
tween the  cap  and  clasp. 

A  Bicuspid  or  Molar  Partial  Gap  and  Clasp  Attachment. — Fig. 
442  illustrates  the  form  the  attachment  just  described  usually 
assumes  in  cases  of  bicuspid  and  molars.  The  dotted  line 
marks  the  boundary  of  the  partial  pure  gold  cap.  The  con- 
struction follows  similar  lines  to  those  laid  down  in  the  case  of 


Fig.  440 


Fig.  441. 


Fig.  442. 


a  cuspid.  If  preferable,  the  cap  section  can  be  burnished  down 
against  the  crown;  and  if  necessary,  it  can  be  slit,  and  solder 
can  be  flowed  over  it  at  the  final  adjustment  of  the  bridge.  This 
form  of  attachment  is  especially  useful  in  eases  where  a  natural 
tooth  tips  out  of  line  so  as  to  render  it  difficult  to  entirely  en- 
circle it  with  a  continuous  band. 

Pure  gold  has  been  given  the  preference  to  thin  platinum  in 
the  construction  of  these  partial  caps,  for  the  reason  that  the 
form  and  the  position  of  the  former  are  less  liable  to  be  altered 
in  soldering,  an  advantage  which  is  relatively  more  important 
than  the  non-fusible  quality  of  the  platinum. 

The  forms  of  attachments  described  for  removable  bridge- 
work  are  those  most  generally  applied  in  practice.  The  methods 
for  their  construction,  which  as  given  arc  the  result-  of  practical 
experience,  may  in  some  respects  differ  from  those  followed  by 


216  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

others.  In  application,  as  will  be  shown,  they  enable  the 
operator  to  avoid  difficulties  often  encountered  in  obtaining  a 
proper  adjustment  of  removable  bridges  on  the  abutments  and 
alveolar  border.  Special  forms  of  attachments  not  in  general 
use  will  be  described  in  the  succeeding  chapters,  in  their  applica- 
tion to  practical  cases.  Their  use  in  combination  with  the  forms 
already  explained  may  at  times  prove  advantageous. 

Connecting  Bars. — Connections  between  the  different  sections 
of  a  removable  bridge  are  formed  in  the  following  manner:  A 
plaster  impression  of  the  case  or  the  part  to  be  spanned  is  taken 
in  plaster,  and  a  cast  made  by  pouring  into  it  fusible  metal  which 
melts  at  a  point  less  than  or  not  over  two  hundred  degrees  (see 
chapter  on  Molds  and  Dies).  The  cast  must  correctly  represent 
the  lingual  or  palatal  surfaces  of  the  teeth.  Upon  this  cast  a  strip 
of  pure  gold,  No.  30  gauge,  about  one-quarter  of  an  inch  in  width 
and  of  the  proper  length  for  the  required  connecting-bar,  is  bur- 
nished over  the  palatal  or  lingual  surface  of  the  teeth  intervening 
between  sections  of  the  bridge  or  attachment  to  be  connected. 
Wax  is  placed  on  the  surface  of  the  gold,  and  the  gold  is  removed 
and  invested.  The  wax  is  next  removed,  and  a  piece  of  gold 
clasp  plate,  a  trifle  narrower  than  the  strip  of  pure  gold,  is  bent 
and  shaped  to  fit  over  its  surface.  Twenty-carat  solder  is  then 
flowed  over  the  gold  in  quantity  sufficient  to  join  the  parts,  level 
the  surface,  and  make  a  rigid  bar  capable  of  resisting  such  force 
in  use  as  would  tend  to  destroy  its  shape  in  the  slightest  degree. 
When  the  bar  is  formed  on  the  metallic  cast  it  can  be  trans- 
ferred to  the  plaster  model,  and  then,  or  in  the  subsequent  con- 
struction of  the  work,  connected  to  the  attachments ;  or  the  bar 
can  be  adjusted  in  the  mouth,  cemented  with  wax  or  ligatured 
on  the  teeth,  the  attachments  placed  in  position,  and  the  bar  and 
attachments  removed  in  their  relative  positions  in  a  plaster  im- 
pression. On  the  model  made  from  this  impression  they  will 
be  found  the  same  as  in  the  mouth.  The  construction  of  the 
bridge  can  then  be  continued.  Fig.  443  represents  a  bar  of  this 
character  to  span  the  lower  front  teeth  and  connect  attachments 
on  the  cuspid  and  bicuspid. 

For  the  Upper  Front  Teeth. — Where  a  bar  narrower  than  the 
one  described  is  required,  the  strip  of  pure  gold  should  be  cut 


REMOVABLE  BICUSPID  AND  MOLAR  ATTACHMENTS.      217 

proportionately,  and  pieces  of  half- round  iridio-platinum  or  gold 
clasp  wire  used  to  form  and  stiffen  the  bar,  instead  of  gold  clasp 
plate. 

Construction  of  Removable  Bridge-Work. — In  removable,  as  well 
as  other  styles  of  bridge-work,  the  method  of  procedure  is  en- 
tirely governed  by  the  conditions  presented  in  each  case.     There- 

Fig.  443. 


fore  directions  given  regarding  bridge-work  embracing  certain 
teeth  and  attachments  in  one  instance  may  vary  considerably 
from  what  is  required  for  the  same  teeth  in  another;  conse- 
quently the  process  of  construction  can  only  be  outlined  in 
somewhat  general  terms. 

A  case  frequently  presented,  involving  the  loss  of  a  portion 
of  the  lower  teeth,  as  shown  in  Fig.  444,  will  be  taken  to  illus- 

Fig.  444. 


trate  the  method  generally  adopted  for  the  construction  of  re- 
movable bridge-work. 

The  molar  is  shaped  to  receive  a  gold  crown.  The  anterior 
approximal  side  is  trimmed  parallel  with  the  line  of  the  posterior 
side  of  the  cuspid.  Removing  a  little  of  the  enamel  on  the 
distal  side  of  the  cuspid  will  assist  the  operation  and  straighten 


218  AR TIFJCIA L  CRO  WN-  A ND  BRIDGE-  WORK. 

that  part  of  the  tooth.  A  straight-sided  gold  crown  is  made 
for  the  molar.  A  plaster  impression  is  then  taken,  which  will 
remove  the  gold  molar  crown  in  position,  and  a  cast  is  made  as 
follows :  The  form  of  the  cuspid  and  interior  of  the  gold  crown 
are  first  rilled  with  fusible  metal,  and  the  remainder  of  the  im- 
pression with  pure  plaster,  as  described  in  chapter  on  Molds 
and  Dies. 

The  bite  is  taken  in  wax,  and  an  articulating  model  made.  A 
removable  partial  cap  is  made  for  the  molar,  and  a  partial  cap 
and  clasp  attachment  for  the  cuspid.  Dummies  are  then  fitted 
and  soldered  together,  placed  in  position,  and  joined  to  the 
attachments  with  wax  cement.  The  bridge  is  then  removed 
from  the  model,  invested,  and  soldered  together.  Connection 
with  the  attachment  is  only  to  be  made  at  the  collar  section. 
The  gold  crown  and  fusible  metal  are  then  separated  from  the 
model  and  the  fusible  metal  removed  from  the  crown  in  the 
manner  described  on  page  214. 

The  molar  crown  and  the  bridge  are  then  fitted  to  the  mouth. 
The  crown  is  next  cemented  on  the  molar  and  the  bridge  im- 
mediately adjusted  over  it,  pressed  into  position,  and  allowed  to 
remain  until  the  cement  has  set.  The  partial  cap  section  of  the 
attachments  is  burnished  down  on  the  bicuspid  and  the  gold 
crown  on  the  molar,  while  the  bridge  is  kept  firmly  pressed 
against  the  gums.  The  bridge  is  then  removed,  invested,  and 
the  partial  cap  sections  made  rigid  by  flowing  gold  solder  over 
them.  The  final  trimming,  finishing,  and  polishing  of  the  bridge 
is  then  performed,  and  it  is  ready  for  insertion. 

The  procedure  in  the  case  described  can  be  varied  by  making 
the  entire  model  of  fusible  metal,  or  by  placing  a  little  wax  in 
the  interior  of  the  grinding-surface  of  the  gold  crown,  making 
a  plaster  model,  removing  the  gold  crown  and  filling  it  with 
fusible  metal,  making  the  attachment  and  replacing  the  gold 
crown  on  the  model.  The  cuspid  attachment  can  be  formed  on  a 
fusible  metal  cast  .of  the  tooth. 

The  methods  of  construction  as  above  given  may  be  still 
further  varied  by  first  forming  the  gold  crown  and  attachments, 
fitting  them  in  position  in  the  mouth,  taking  a  plaster  impres- 
sion which  will   remove  them   in  position,  and  then  making  a 


REMOVABLE  BICUSPID  AND  MOLAR  ATTACHMENTS.       219 


model  of  plaster  and  calcined  marble-dust.  On  this  the  dum- 
mies can  be  fitted  and  soldered  to  the  attachments.  The  gold 
crown  is  to  be  removed  from  the  model  after  the  position  of  the 
attachment  on  it  is  secured  by  the  investing  material. 

Removable  bridge-work  is  best  constructed  with  the  bases  of 
the  dummy  teeth  pressing  firmly  on  the  tissue  of  the  gum.  If 
the  collar  of  the  molar  attachment  should  prove  difficult  to 
remove  when  first  inserted,  it  should  be  slit  at  the  posterior 
section,  slightly  expanded,  and  reunited  with  solder,  when  the 
-cap  sections  of  the  attachments  are  stiffened  in  the  final  process 
of  soldering.  A  small  piece  of  gold  plate  can  be  inserted  in  the 
aperture  of  the  collar  to  aid  the  gold  to  unite  the  ends. 

In  Fig.  445  are  illustrated  the  two  forms  of  removable  bridge- 

Fig.  445. 


work  that  could  be  constructed  for  the  same  case.  In  the  one 
a  clasp  attachment  is  placed  on  the  natural  cuspid,  in  the  other 
the  natural  crown  is  excised  and  a  removable  cuspid  crown  con- 
structed. In  the  construction  of  either  style,  a  gold  crown  is 
made  for  the  molar,  with  a  removable  gold  partial  cap  and  collar 
attachment.  A  removable  partial  cap  and  clasp  attachment  is 
made  for  the  cuspid,  or,  if  the  natural  crown  is  excised,  a  re- 
movable cuspid  crown,  and  the  cap  and  tube  section  cemented 
in  position  on  the  root.  The  crown  or  crowns  and  attachments 
arc  adjusted  in  position  in  the  mouth.  If  the  cuspid  attachment 
is  used,  and  it  seems  liable  to  become  misplaced,  it  can  be  liga- 
tured to  the  natural  crown.  An  impression  and  bite  are  then 
taken  in  plaster,  and  when  removed  from  the  mouth  the  crowns 


220  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

ami  attachments  are  to  be  replaced  in  position  in  the  impression, 
and  a  model  of  plaster  and  calcined  marble-dust  made,  and  also 
an  articulating  model  in  plaster.  The  lateral  and  bicuspid  and 
molar  dummy  teeth  are  next  fitted  in  proper  position  on  the 
model.  A  piece  of  pure  gold  is  adapted  against  the  lateral,  and 
burnished  over  the  palato-approximal  side  of  the  central  to  form 
the  flange.  The  case  is  then  invested,  the  gold  crown  slipped 
out  of  the  attachment,  the  place  it  occupied  is  filled  with  ad- 
ditional investing  material,  and  the  parts  are  all  soldered  to- 
gether. The  construction  can  be  varied  by  first  making  the 
bridge  from  the  molar  to  the  cuspid,  and  then  adding  the  lateral 
and  flange.  When  finished,  a  suitable  quantity  of  cement  is 
placed  in  the  gold  crown,  the  crown  is  fitted  on  the  molar,  the 
bridge  adjusted  in  position,  and  the  teeth  occluded  and  so  allowed 
to  remain  until  the  cement  sets. 

Fig.  446. 


The  denture  illustrated  in  Fig.  446,  a  case  of  Dr.  A.  S.  Rich- 
mond's, was  made  to  restore  a  loss  of  teeth  which  is  frequently 
met  with,  but  one  not  suitable  for  the  insertion  of  cemented 
bridge-work.  The  application  of  a  removable  denture  combin- 
ing bridge-  and  plate-work  is  a  method  possessing  advantages 
over  those  ordinarily  practiced.  In  brief,  the  constructive 
details  are  :  A  connecting  bar  is  formed  as  described  on  page  216. 
In  the  case  in  hand,  when  the  pure  gold  to  form  the  connecting 
bar  was  adapted  to  the  cast,  it  was  extended  around  and  over 
the  cuspid  and  bicuspid.  Gold  clasps  were  then  adapted  over 
this,  and  the  soldering  done  at  the  same  time  as  the  bar.  The 
bar  and  clasp  attachments  were  inserted  in  the  mouth,  an  im- 
pression taken  in  plaster,  and  a  model  made  with  the  attach- 


REMOVABLE  BICUSPID  AND  MOLAR  ATTACHMENTS.       221 

meats  and  bar  on  it  in  position.  Metal  casts  were  also  made  of 
the  parts  at  A,  A,  Fig.  447,  and  two  gold  plates  struck  up.  The 
teeth  were  then  arranged  in  position,  the  bicuspids  resting  on 
the  gums  and  the  molars  on  the  two  plates  or  saddles,  and  the 
denture  completed  as  shown  in  the  illustration. 

Fig.  447. 


Removable  bridge-work  offers  peculiar  advantages  for  arti- 
ficial replacement  of  lower  incisors  in  cases  similar  to  that 
illustrated  in  Fig.  448.  A  portion  of  the  contour  of  the  ap- 
proximal  sides  of  the  right  cuspid  is  removed.     Shell  caps  for 


Pig.  448. 


the  right  and  left  cuspids  are  then  formed  of  crown  gold, 
reaching  nearly  to  the  margin  of  the  gum.  The  caps  are  en- 
circled with  a  narrow  strip  of  stiff  gold  plate  or  clasp  metal, 
about  No.  35  gauge,  which  is  soldered  to  the  caps  as  described 
on  page-    213  in  the  construction  of  molar   partial  caps.     The 


999 


.1  R  TIFK  'IAL   CEO  ir.V-  .  [  SD  BRIDGE-  WORK. 


caps  are  next  adjusted  in  the  mouth,  and  an  impression  and  Itite- 
taken  in  plaster  and  the  caps  removed  in  it. 

A  model  of  half  plaster  and  marble-dust  and  an  articulation 
in  plaster  are  then  made.  Porcelain  incisor  teeth  with  straight 
pins  are  fitted  in  position,  backed,  and  a  broad  bar  extending 
from  the  lingual-approximal  side  of  the  gold  cap  on  the  left 
cuspid  around  to  the  mesial  side  of  the  lateral  is.  formed  of  a 
strip  of  pure  gold,  adapted  to  the  parts,  overlaid,  and  soldered 
to  a  slightly  narrower  strip  of  gold  clasp  plate.  The  different 
portions  are  then  cemented  together  with  wax,  invested  on  the 
model,  and  properly  united  with  solder.  When  finished  and 
inserted  in  the  mouth,  it  constitutes  a  denture  that  can  be  worn 

Fig.  449. 


without  inconvenience  by  the  patient,  and  removed  daily  and 
cleansed,  which  last  especially  is  a  great  advantage,  as  in  a  case 
like  this  the  teeth  replaced  have  usually  been  lost  by  pyorrhea 
alveolaris  and  those  remaining  are  affected  by  the  same  trouble. 
The  natural  teeth,  if  loose,  are  in  a  measure  steadied  and  sup- 
ported by  the  appliance.  In  some  cases,  especially  if  the  teeth 
tip,  one  or  both  of  the  attachments  on  the  cuspids  can  be  made 
of  thick  clasp  metal  in  the  form  of  a  clasp  attachment,  as  des- 
cribed on  page  214. 

In  the  case  represented  in  Fig.  449,  gold  crowns  with  remov- 
able partial  cap  and  collar  attachments  are  made  for  the  molar 
and  bicuspid,  and  removable  crowns  with  flanges  of  the  metal  on 
the  palatal  sides  for  the  centrals  and  cuspid.     The  right  central 


REMOVABLE  BICUSPID  ASD  MOLAR  ATTACHMENTS.       223 


is  capped  and  the  crown  fitted  over  it  without  a  post,  as  the 
posts  in  the  other  two  crowns  afford  ample  security. 

After  the  crowns  are  made,  the  root-caps  are  cemented  on 
each  root.     The  central  crowns  are  cemented  together  with  wax. 


Fig.  450. 


adjusted  in  position,  covered  with  a  small  quantity  of  investing 
material,  removed,  more  investing  material  added,  and  the  crowns 
soldered  together. 

The  centrals  and  the  cuspid  are  then  adjusted  in  the  mouth, 
a  lateral  is  hacked,  fitted,  and  waxed  between  them  in  position, 

Fig.  451. 


the  whole  removed  in  investing  material,  and  the  process  of 
investing  and  soldering  proceeded  with  to  join  the  parts  as 
before  described.  This  bridge  of  four  teeth  is  fitted  to  the 
mouth,  and  the  points  of  the  posts  trimmed  on  the  side  and  in 


■2 24  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

the  direction  which  will  best  favor  their  entrance  into  the  tubes 
in  each  root,  so  that  the  bridge  will  readily  slip  into  position. 
The  dummy  bicuspids  and  molar  on  the  right  side  between  the 
cuspid  and  molar  are  then  added  by  first  taking  an  impression 
and  bite  of  that  section,  and  then  proceeding  with  the  construc- 
tion as  described  in  previous  cases.  The  section  of  the  bridge 
with  the  extension  on  the  left  side  is  next  added  in  a  similar 
manner  by  taking  an  impression  of  the  part  while  the  portion 
of  the  bridge  already  constructed  is  in  position,  removing  bridge 
and  impression  together,  and  making  a  model.  A  piece  of  pure 
gold  is  shaped  to  the  model  by  successive  burnishing  and  an- 
nealing, to  form  a  base  for  the  molar.  The  one  molar  will  exert 
as  much  leverage  on  the  abutment  of  the  bridge  in  mastication 
as  can  safely  be  borne. 

Fig.  450  shows  the  bridge  completed,  and  Fig.  451  the  piece 
in  position. 


CHAPTER    X. 


REMOVABLE  PLATE  BRIDGES. 


In  this  style  of  bridge  a  plate  is  used  to  span  the  space  and 
support  the  artificial  teeth  between  the  abutments.  An  essential 
requisite  of  this  class  of  dentures  is  that  the  plate  portion  shall 
rest  closely  and  firmly  on  the  alveolar  border,  and  at  the  same 
time  receive  support  from  the  abutments.  Attachments  similar 
to  those  used  in  connection  with  removable  bridge-work  are  also 
applicable  to  removable  plate  bridges.  The  methods  to  be  given 
describing  their  application  will  differ  in  some  respects,  which 
will  be  advantageous  in  a  practical  way. 


Fig.  452. 


Fig.  453. 


The  case  shown  in  Fig.  452  will  be  taken  to  describe  the  con- 
structive details  of  a  denture  of  this  class.  In  the  root  of  the 
central  a  tube  is  inserted,  attached  to  a  cap  on  the  end  of  the 
root.  Over  this  cap  is  placed  an  outer  cap  which  has  a  split 
spring  pivot  or  post  fitting  the  tube.  A  narrow  plate  between 
the  teeth  connects  the  outer  cap  to  a  clasp  attachment  which  fits 
around  and  rests  upon  the  cuspid. 

16  225 


226 


.  1  R  TJFICIA  L  CRO  WN-  AND  BRIDGE-  WORK. 


The  cuspid,  which  because  of  its  conical  form  is  one  of  the 
most  difficult  teeth  in  the  mouth  to  clasp,  is  trimmed  sufficiently 
to  partially  square  its  approximal  sides,  and  the  palatal  portion  is 
notched  slightly  (A,  Fig.  453),  to  form  a  shoulder  for  the  clasp 
to  rest  upon.  This  notch  can  be  safely  made,  as  the  enamel  is 
very  dense  at  the  point  indicated. 

A  gold  plate  is  swaged  to  fill  the  space  between  the  central 
root  and  the  cuspid  as  shown  in  Fig.  452.  The  cap  and  pivot 
are  adjusted  on  the  central  root,  and  the  plate  is  then  fitted  in 
the  mouth,  pressed  tightly  in  position  against  the  gum,  and 
retained  there  with  a  little  wax,  which  is  cemented  to  the  plate 

Fig.  454. 


and  pressed  against  the  cuspid  and  side  of  the  cap.  An  im- 
pression of  the  parts  and  an  articulation  are  then  taken  in 
plaster.  The  cap,  pivot,  and  plate  being  removed  in  the  im- 
pression, they  will  be  presented  on  the  model  made  from  it  in 
exactly  the  same  position  as  in  the  mouth.  A  second  or  outer 
cap  is  then  fitted  over  the  root-cap,  the  band  being  made  very 
narrow  at  the  approximal  and  palatal  sides,  and  open  at  the 
labial  side,  as  the  porcelain  tooth  to  be  attached  will  serve  in  its 
stead  (B).  The  pin  is  then  soldered  fast  in  the  outer  cap,  and  a 
clasp  of  clasp  gold  (C),  No.  23  to  Xo.  24  gauge,  is  formed  to  extend 
well  around  the  posterior  approximal  portion  of  the  cuspid. 
The  outer  cap  having  been  placed  in  position  on  the  inner  one, 
the  plate  extending  from  the  central  to  the  cuspid  is  cemented 
to  it  and  to  the  clasp  with  wax,  removed,  invested,  and  the  parts 


REMOVABLE  PLATE  BRIDGES.  227 

soldered  together.  Aided  by  the  plaster  articulation,  teeth  are 
ground  and  fitted  on  the  model,  backed,  attached  to  the  plate 
with  wax,  and  inserted  in  the  mouth.  Platinum  foil  is  then 
burnished  to  the  form  of  the  notch  on  the  cuspid,  the  clasp 
fitted  over  it  and  attached  with  wax,  removed  with  the  plate, 
and  soldered  to  it  simultaneously  with  the  teeth. 

When  the  piece  is  finished  and  fitted  in  the  mouth,  the  inner 
cap — the  end  of  the  tube  having  been  closed  with  gutta-percha 
— is  first  cemented  on  the  central  root.  A  very  small  quantity 
of  oxyphosphate  is  used,  and  while  it  is  yet  soft  the  plate  is 
adjusted  in  position,  and  allowed  to  remain  there  until  the 
cement  has  set.  The  split  pivot  is  sprung  open  a  little  and 
forced  to  place.  With  the  aid  of  the  clasp  around  the  cuspid  it 
will  be  found  to  perfectly  secure  the  plate.     Figs.  454  and  455 

Fig.  455. 


show  the  bridge  finished  and  in  position.  If  the  plate  forming 
the  bridge  is  tightly  adjusted  against  the  soft  tissues,  and  removed 
in  that  position  in  the  impression  taken  with  the  caps,  it  will 
always  be  found  to  fit  in  a  similar  manner  when  the  bridge  is 
finished.  Should  the  clasp  cause  decay  or  abrasion  of  the  cuspid, 
the  tooth  can  be  excavated  to  a  slight  depth  under  the  clasp,  and 
filled  with  gold.  This  is  best  done  by  making  a  few  retaining- 
pits,  filling  them  with  a  hand-plugger,  and  then  inserting  the 
main  body  of  the  gold  in  the  ordinary  manner,  the  Herbst  method 
being  useful  in  condensing  the  foil.  Such  a  filling  inserted  at 
any  time  will  prevent  injury  from  a  clasp.  A  denture  of  this 
style  can  be  made  to  pass  intervening  teeth. 

In  the  artificial  replacement  of  the  lower  teeth  in  a  ease  such 
as  is  illustrated  in  Fig.  456,  a  plate  bridge  possesses  many  advan- 
tages. In  the  construction  of  such  a  denture,  the  teeth  are  first 
properly  shaped.     Gold  crowns  (Fig.  457),  with  sides  as  nearly 


228 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


as  possible  parallel  the  one  with  the  other,  are  then  made  and 
fitted  to  the  bicuspid  and  molar.  This  operation  is  frequently  fa- 
cilitated by  shaping  the  external  surface  of  the  crown  with  metal. 
On  the  crowns,  at  the  buccal  sides,  a  narrow  shoulder  (A)  is  con- 
structed to  sustain  the  collars  and  bridge  in  position.     In  some 

Fig.  4-5R. 


cases  this  shoulder  is  placed  on  the  approximal  side  to  better 
advantage.  The  crowns  are  then  adjusted  in  the  mouth,  a  small 
quantity  of  wax  being  applied  inside  of  the  crowns  when  neces- 
sary to  retain  them  in  correct  position.     A  piece  of  plate  is  next 


Fig.  457. 


swaged  and  fitted  between  the  crowns  and  attached  with  wax  as- 
described  in  the  previous  case.  An  impression  and  articulation 
of  that  part  of  the  mouth  are  then  taken  with  plaster  and  the 
crowns  and  plate  removed  in  it.  On  the  model  made  from  this 
impression  the  crowns  and  plate  will  appear  in  position.     Collars 


REMOVABLE  PLATE  BRIDGES. 


229 


reaching  from  the  cervical  to  the  occluding  edge  are  fitted  to 
these  crowns. 

The  collars,  though  fitting  accurately,  should  move  easily  over 
the  crowns,  as  they  can  be  readily  tightened  when  the  case  is 
finished.  If  a  collar  is  troublesome  to  adjust  and  remove,  cut 
the  side  opposite  to  that  attached  to  the  plate,  and  spring  it  open 
a  little.  After  fitting  the  teeth  it  can  be  again  united  when  they 
are  being  soldered.  This  collar  and  shoulder  form  a  support  in 
some  respects  preferable  to  a  partial  or  an  entire  double  cap, 
being  less  difficult  to  keep  clean.  A  collar  is  more  easily  con- 
structed, and  also  permits  the  position  of  the  bridge  to  be  altered 
by  the  removal  of  a  little  of  the  shoulder  or  of  the  upper  edge 
of  the  collar,  and  is  a  secure  but  less  rigid  attachment  than  is 
provided  by  other  methods. 

Fig.  458. 


The  collars  and  plate  are  next  cemented  with  wax,  removed, 
invested,  and  strongly  soldered  together  (B,  B,  Fig.  457).  The 
artificial  teeth  are  fitted  in  proper  position  on  the  plate  by  the 
aid  of  a  plaster  articulation,  attached  with  wax,  and,  if  preferred, 
the  piece  may  be  adjusted  in  the  mouth  without  the  gold  crowns. 
The  bridge  is  then  invested  and  finished. 

The  attachment  of  the  artificial  teeth  to  a  plate  of  this  kind 
•can  be  of  either  gold  or  rubber.  Whichever  is  adopted,  the  first 
bicuspid  is  best  supported  by  being  soldered  to  the  collar.  If 
iridio-platinum  is  used  in  the  construction  instead  of  gold  plate, 
and  the  soldering  done  with  pure  gold,  porcelain  body  can  be  used. 
When  ready  to  be  inserted,  the  crowns  are  adjusted  with  cement, 
and  then  the  bridge,  which  is  left  in  position  until  the  cement  sets. 
By  burnishing  the  collars  they  can  be  made  to  clasp  the  crowns 
as  firmly  as  desired.     Fig.  458  shows  the  denture  in  position. 


•230 


ARTIFICIAL   CROWN-  AND  BRIDGE-WORK. 


Figs.  459  and  460  represent  an  upper  removable  plate  bridge. 
In  its  construction  the  cuspid  roots  were  first  capped,  tubed,  and 
pivoted,  and  the  molars  crowned  with  shoulders  formed  on  the 
buccal  sides.  The  plate  intended  to  connect  the  abutments  was 
then  adjusted  in  position  as  has  been  described.  An  impression 
was  next  taken  and  a  model  and  articulation  made.    The  cuspids 

Fig.  459. 


were  then  double-capped  and  collars  formed  on  the  molar  crowns. 
The  double  caps,  pivots,  collars,  and  plate  were  next  soldered 
together.  The  artificial  teeth  were  attached  with  vulcanite,  the 
gum  section  being  formed  with  pink.  In  order  to  avoid  any 
warping,  which  might  readily  occur  in  the  construction  of  so 
large  a  denture  as  this,  the  plate  may  at  first  be  swaged  up,  as 

Fig.  460. 


in  ordinary  artificial  dentures,  to  cover  the  whole  of  the  hard 
palate.  A  shallow  groove  can  be  made  around  the  palatal  sur- 
faces of  the  teeth,  and  after  the  final  soldering  the  plate  can  be 
cut  along  the  line  of  this  groove,  the  portion  covering  the  palate 
being  removed.  The  groove  will  insure  a  close  fit  for  the  palatal 
edge  of  the  plate. 


REMOVABLE  PLATE  BRIDGES. 


231 


In  the  case  represented  in  Fig.  461  the  natural  teeth  were 
very  short.     The  posterior  approximal   side  of  the  molar  was 

Fig.  461. 


decayed  to  such  an  extent  that  the  pulp  was  nearly  exposed,  and 
considerable    irritation  of  the  investing  gum-tissue   had    been 


232 


ARTIFICIAL  CROWN-  AND  IiRIDGE-WORK. 


caused  by  the  clasp  of  a  plate  worn  by  the  patient  working 
upward  against  it.  The  patient  declined  to  have  a  plate  made 
which  would  extend  across  the  palate.  The  lateral  was  hardly 
strong  enough  to  support  a  permanent  bridge.  The  molar  was 
capped,  and  a  removable  appliance  constructed  with  a  band 
which  slipped  over  the  cap  and  rested  on  a  shoulder  on  the 
mesial  side  to  form  the  posterior  abutment.  The  lateral  was 
notched  and  clasped  for  the  anterior  support.  Figs.  462  and 
463  are  two  views  of  the  appliance  in  position. 


Fig.  464. 


^TX 


Fig.  405. 


Fig.  464  represents  a  case  in  which  the  bicuspids  and  a  molar 
are  replaced,  and  also  a  central,  on  an  extension  of  the  plate, 
the  cuspid  being  partly  encircled  by  a  clasp  with  a  shoulder 
resting  on  the  palatal  section  of  the  tooth.  Fig.  465  shows  the 
denture  in  position. 

Fig.  466  represents  a  case  in  which  a  bridge-plate  was  in- 
serted without  crowning  either  of  the  abutments.  The  clasp  of 
a  plate  which  had  been  worn  for  some  years  had  worked  upward 
and  abraded  the  distal  section  of  the  cuspid  to  such  an  extent  as 
to  expose  a  large  portion  of  the  root  and  superinduce  decay. 


REMOVABLE  PLATE  BRIDGES. 


233 


The  cavity  was  filled  with  gold,  and  the  gingival  border,  by 
treatment,  brought  nearly  to  its  normal  position  on  the  tooth. 
A  plate  bridge,  such  as  is  represented  in  Figs.  467  and  468,  was 
then  constructed.  Clasps,  with  flanges  resting  on  little  shoulders 
formed  at  A,  A,  Fig.  466,  support  and  retain  it.  A  flange  such 
as  was  used  in  this  case  is  best  made  subsequent  to  the  con- 
struction of  the  plate  and  clasps,  by  burnishing  a  piece  of 
platinum  foil  in  the  mouth  to  the  form  of  the  shoulder  and  the 
side  of  the  tooth  upon  which  it  is  to  rest,  adjusting  the  clasp  over 


Fig.  467. 


Fig.  468. 


it,  and  cementing  with  wax,  then  removing,  investing,  and 
soldering.  Wherever  the  platinum  is  placed,  the  solder  will  flow 
and  fill  all  the  space  between  it  and  the  clasp.  This  gives  the 
clasp  the  exact  form  of  the  tooth. 

Fig.  469  shows  the  denture  finished  and  in  position.  If  the 
teeth  are  dense  in  structure,  an  attachment  of  metal  held  in 
proper  position  against  the  lower  portion  of  a  crown  will  be 
worn  a  long  while  before  it  causes  injury  to  the  parts.  Filling, 
or  crowning,  if  necessary,  can  subsequently  be  resorted  to. 

By  a  correct  application  of  the  methods  just  explained  and 


234 


A  R  TIFICIA  L  CRO  WN-  A  ND  BR  ID  G  E-  WORK. 


illustrated,  a  piece  of  removable  bridge-work  of  this  style  can 
be  devised  for  many  cases. 

Dr.  J.  L.  Davenport  describes  the  methods  he  adopted  in  the 
application  of  plate  bridges  to  the  following  case : 

"  The  patient  was  a  gentleman  about  fifty-five  years  of  age. 
The  upper  jaw  contained  the  six  front  teeth,  the  three  molars  on 
the  right  side,  and  the  first  bicuspid  on  the  left.  The  lower  jaw 
contained  all  but  the  left  central  incisor,  the  second  bicuspid,  the 
three  molars  on  the  right  side,  and  the  first  and  third  molars  of 
the  left. 

"In  consequence  of  this  lack  of  occluding  back  teeth,  mastica- 
tion had  been  performed  solely  by  the  front  teeth,  causing  attri- 

Fig.  470. 


(MlfK 


'■"'■"  '!■' 


tion  so  great  on  the  upper  ones  as  to  entirely  obliterate  their 
crowns,  while  the  lower  ones  suffered  but  little  loss,  as  will  be 
seen  by  reference  to  Fig.  470. 

"  The  patient  had  managed  for  a  long  time  to  masticate,  though 
imperfectly,  upon  these  stumps,  but  latterly  could  eat  scarcely 
anything  but  soups  and  soft  foods. 

"  The  restoration  of  the  lower  teeth  being  completed  to  the 
extent  of  about  one-eighth  of  an  inch  on  an  average,  to  make 
them  of  uniform  height,  my  attention  was  directed  to  the  upper 
incisors  and  cuspids,  nearly  all  of  which  I  found  with  dead 
pulps,  and  some  of  them  in  a  condition  of  active  abscess. 

"The  two  superior  cuspid  roots  were  dressed  down  nearly  to 
the  gum,  and  fitted  with  22-carat  gold  cap  crowns.     After  these 


REMOVABLE  PLATE  BRIDGES.  035 

had  been  placed  in  position,  a  hole  was  drilled  through  each  cap 
of  a  size  suited  to  that  of  the  pulp-canal,  and  a  tube  of  iridium 
and  platinum  was  adjusted  in  the  root  and  cap  and  waxed  in 
position.  The  cap  and  tube  were  then  taken  off  and  soldered, 
great  care  being  taken  to  have  the  tubes  enter  both  roots  per- 
fectly parallel.  These  were  permanently  secured  in  the  roots 
with  gutta-percha,  and  to  prevent  the  caps  being  pulled  off  the 
top  of  each  tube  was  slit  down  a  trifle,  and  after  insertion  was 
bent  back  into  the  gutta-percha  with  a  warm  instrument. 

"The  incisor  roots  having  been  dressed  down  even  with  the 
gum  and  filled,  a  plaster  cast  was  taken  and  a  narrow  20-carat 
gold  plate  was  swaged  to  fit  over  the  ends  of  the  incisors  and  the 
capped  cuspids,  making  it  a  little  broader  where  it  had  to  rest 
on  the  gum  back  of  the  first  left  bicuspid  root.  A  hole  in  the 
plate  was  then  made  to  expose  the  root  of  the  first  left  bicuspid. 
This  was  fitted  with  a  bifurcated  iridio-platinum  pin,  having 
notched  sides,  and  a  hammered  head  upon  its  lower  end,  which 
came  down  below  the  root  about  three-eighths  of  an  inch. 

"A  thin  iridio-platinum  band  was  then  made  to  encircle  the 
root,  passing  just  under  the  gum  and  being  slightly  longer  than 
the  headed  pin.  This  band  was  perforated  with  two  rows  of 
holes,  from  without  inward,  giving  the  inner  surface  a  rough- 
ness similar  to  that  of  a  nutmeg-grater.  The  band  and  pin  were 
then  made  secure  to  the  root  with  a  non-shrinkable  copper 
amalgam. 

"Fig.  471  shows  the  upper  jaw  ready  for  the  plate. 

"After  the  amalgam  had  become  hard  and  the  end  and  sides 
had  been  polished,  a  gold  crown  was  fitted  over  all  just  up  to 
the  margin  of  the  gum,  and  in  close  contact  with  the  end  of  the 
band  and  amalgam.  This  crown  was  loose  enough  to  admit  of 
its  sliding  on  and  off,  though  with  just  enough  friction  to  hold  it 
in  place  when  at  rest.  This  gold  crown  was  then  placed  in  posi- 
tion, the  plate  also  inserted,  and  hard  wax  used  to  firmly  join 
the  two  in  the  mouth.     They  were  then  removed  and  soldered. 

"  Gold  pins' were  then  placed  through  holes  drilled  in  the  plate 
into  the  tubed  cuspids;  then  soldered  to  the  plate,  the  pins  being 
of  a  size  to  fit  the  tubes  accurately.  The  plate  was  also  provided 
with  a  wide  clasp  encircling  the  first  molar  on  the  right. 


236 


ARTIFICIAL  CROWX-  AXD  BRIDGE- WORK. 


"  The  plate  was  then  provided  with  a  gold  bar  about  one-eighth 
of  an  inch  wide,  occluding  perfectly  with  the  lower  teeth,  and 
plain  teeth  soldered  in  place,  hiding  the  bar,  and  just  meeting 
the  gum  in  front  of  the  incisor  roots.  The  plate  rested  squarely 
against  the  capped  cuspids,  each  of  which  showed  a  narrow  band 


Fig.  471. 


of  o-old  when  the  plate  was  in  position.  As  finally  completed 
(see  Fig.  472),  this  was  the  most  perfectly  fitting  piece  I  ever 
inserted,  requiring  great  care  in  its  removal,  and  yet  by  a  little 
practice  the  gentleman  was  able  to  remove  and  replace  it  quite 


Fig.  472. 


easily.  It  was  also  as  firm  as  any  permanent  bridge  could  have 
been,  though  it  had  no  support  on  the  left  side  back  of  the  first 
bicuspid. 

"  The  lower  jaw  was  supplied  with  a  double  20-carat  gold  plate, 
having  a  wide  clasp  on  the  first  right  bicuspid,  which,  after  being 


REMOVABLE  PLATE  BRIDGES. 


237 


built  up,  presented  a  cone-shaped  top,  about  which  the  clasp 
fitted  so  as  to  rest  firmly  upon  the  end  of  the  tooth,  thus  pre- 
venting injury  to  the  gums  during  mastication. 

"The  only  other  peculiarity  was  that  the  second  left  inferior 
molar,  being  abnormally  short,  though  well  formed  and  standing 

Fig.  473. 


straight  upright,  was  fitted  with  a  wide  clasp,  extending  almost 
one-eighth  of  an  inch  about  the  tooth,  and  a  piece  of  gold  plate 
with  gold  cusps  was  soldered  into  this  clasp,  covering  the  molar 
crown  and  occluding  with  the  molar  on  the  upper  plate  (see 
Fig.  473).     This  not  only  prevented  the  plate  from  being  bitten 

Fig.  474. 


down  unpleasantly  on  the  gums  during  mastication,  but  enabled 
me  to  use  a  shorter  molar  upon  the  upper  than  I  otherwise  could 
have  done,  and  allowed  better  the  anteroposterior  and  lateral 
movements  of  the  jaws. 

"Fig.  474  shows  the  case  as  completed." 


CHAPTER   XL 

SPECIAL  FORMS   OF  DETACHABLE  AND    REMOVABLE 
BRIDGE-WORK. 

A  description  of  special  forms  and  methods  of  constructing 
detachable  and  removable  bridge-work  is  given  in  the  following 
articles,  as  practiced  by  the  introducers  or  as  adopted  in  general 
practice. 

DR.    WINDER'S    SECTIONAL    CROWN    METHOD. 

This  method,  an  invention  of  Dr.  R.  B.  "Winder's,  presents 
the  novel  feature  of  constructing  the  crowns  and  forming  the 
abutments  in  sections,  the  bridge  being  attached  to  the  detach- 
able section. 

Fig.  475. 


Fig.  475  illustrates  a  case  of  bridge-work  made  in  this  manner. 
The  collar  section  of  the  artificial  crown  is  capped  and  cemented 
on  the  natural  crown  or  root,  the  gold  forming  the  occluding 
portion  of  the  crown,  when  the  bridge  is  adjusted  in  position, 
being  secured  to  it  with  a  screw.  The  screw  may  be  made  to 
enter  the  body  of  the  crown  as  in  Fig.  476,  or  it  may  be 
soldered  to  the  cap  on  the  collar,  passing  through  the  occluding 
section  of  the  crown,  and  being  secured  by  nuts  on  the  screws 
(Fig.  477). 

When  incisor  or  cuspid  roots  form  the  abutments,  Dr.  Winder 
first  forms  a  cap  for  the  end  of  the  root,  to  which  a  tube  is 
attached  extending  up  the  root-canal,  as  illustrated  on  page  209, 
238 


DETACHABLE  AXD  REMOVABLE  BRIDGE-WORK. 


239 


Fig.  425.  On  this  cap  is  mounted  the  crown  (B),  the  post  of 
which  tits  the  tube  tightly.  To  the  crown  so  formed  (Fig.  426) 
the  bridge  is  joined  in  the  usual  manner. 

In  constructing  a  bridge  of  this  style,  the  crowns  forming  the 
.abutments  having  first  been  made,  are  removed  from  the  mouth 
in  a  plaster  impression  and  articulation,  from  which  a  model 


is  made,  showing  the  crowns  in  position.  Each  section  of  the 
bridge  between  the  crowns  is  then  constructed,  and  the  crowns 
adjusted  in  the  mouth.  The  bridges  are  next  inserted  in  posi- 
tion, and  cemented  with  resin  and  wax  to  the  detachable  sections 
of  the  crowns.  The  whole  is  then  removed  in  investing  material, 
in  an  impression-cup,  or  by  placing  the  investing  material  in 

Fig.  477. 


position  on  the  bridge.  After  being  removed  from  the  mouth 
more  investing  material  is  added  and  the  bridge  and  crown  sec- 
tions soldered  together.  Only  the  detachable  sections  of  the 
crowns  should  be  in  the  investment  at  the  time  of  soldering. 

The  incisive  edges  can  be  protected  and  the  occluding  surfaces 
of  the  porcelain  capped  with  gold  as  in  permanently  attached 


240  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

bridge-work,  or  they  can  be  formed  of  the  porcelain,  which  latter 
lessens  the  labor  of  construction,  as  the  bridge  is  easily  detached 
from  the  abutments  for  the  purpose  of  repair.  When  the 
occluding  surfaces  of  bicuspids  or  molars  forming  the  bridge 
are  to  be  capped  with  gold,  the  collar  sections  alone  are  first 
made  and  removed  in  the  impression.  The  caps  for  the  crowns 
and  the  bridge  teeth  are  then  formed  of  one  continuous  piece 
of  gold  plate.  This  is  made  by  laying  the  strip  of  gold  on  a 
piece  of  lead  and  stamping  along  its  length  with  suitable  dies 
representing  the  occluding  surfaces  of  the  different  teeth.  The 
gold  is  then  properly  fitted  to  the  collar  sections  on  the  model, 
conforming  to  the  occlusion  of  the  antagonizing  teeth.  The  cusps 
are  filled  with  solder,  and  the  porcelain  fronts,  backed  with  plat- 
inum plate,  leaving  the  pins  straight,  are  fitted  in  position  to  the 
gold  forming  the  caps  and  the  backings,  and  cemented  with  wax. 
The  porcelain  fronts  are  next  removed,  without  removing  the 
backings,  which  are  invested  and  soldered  to  the  caps.  When 
this  is  completed,  the  holes  in  the  backings  are  deepened  with  a 
drill,  and  the  pins  of  the  porcelain  fronts,  having  first  been' 
slightly  serrated,  are  cemented  in  position  with  oxyphosphate. 
When  the  bridge  is  finished  the  root  and  collar  section  of  each 
crown  is  first  cemented  on  in  position  in  the  mouth;  the  surface 
of  the  detachable  section  of  the  crown  approximating  the  section 
fastened  to  the  bridge  is  then  heated  and  its  surface  covered 
with  a  mere  film  of  gutta-percha.  The  bridge  is  then  adjusted 
in  position  and  secured  by  the  screws  or  nuts.  The  gutta-percha 
prevents  the  secretions  invading  the  interstices  between  the 
sections  of  the  crown. 

Fig.  478  illustrates  another  method,  devised  by  Dr.  W.  R.- 
Spencer, of  constructing  the  sections  of  the  crowns 

T?Tn    4*78  *~ 

in  this  style  of  bridge-work.  The  part  A  slides  in 
the  groove  B.  The  dovetail  flange  A  is  made  of 
a  thick  piece  of  plate,  fitted  to  the  groove  B,  and 
riveted  to  a  piece  of  platinum  adapted  transversely 
across  the  cap  and  then  soldered  to  the  removable 
section  of  the  crown.  Fig.  479  shows  the  sections 
of  the  crown  in  position. 
A  decided  advantage  possessed  by  this  method  of  bridge-work 


DETACHABLE  AND  REMOVABLE  BRIDGE-WORK. 


241 


over  others  is  the  facility  it  affords  in  practice  for  the  ready 
utilization  of  irregular  teeth  as  abutments,  no  matter  how  much 
they  converge  or  diverge,  or  lean  in  or  out  of 
the  line  of  the  arch. 


Fig.  479. 


DR.    LITCH'S    METHOD. 

Dr.  Litch's  method  of  constructino;  detach- 
able  bridge-work  consists  in  forming  a  shell  an- 
chorage over  posts  permanently  fixed  in  cuspid 
roots,  and  anchoring  the  ends  of  the  bridge 
with  bars  in  slots  formed  in  natural  or  artificial  crowns. 

Figs.  480, 481,  and  482  illustrate  a  bridge  similar  to  the  one  illus- 
trated in  Fig.  331  (pagel67)  with  this  style  of  attachment  applied. 


Fig.  480. 


Fig.  481. 


The  anchorage  for  the  cuspids  is  constructed  as  follows :  The 
root  is  first  capped  and  pivoted  as  for  a  collar  crown.  On  the 
palatal  portion  of  the  collar  is  soldered  a  flange  (A,  Fig.  483) 
made  of  gold,  No.  16  U.  S.  standard  gauge,  beveled  off  to  the 
upper  edge  of  the  collar  under  the  free  edge  of  the  gum,  the 
object  being  to  give  a  larger  surface  to  the  top  of  the  cap.  On 
this  cap,  which  covers  the  end  of  the  root,  the  anchorage  post  B, 
which  is  formed  of  iridio-platinum  wire,  No.  9  U.  S.  standard 
gauge,  is  soldered,  over  and  back  of  the  pin  (C)  which  enters 
the  root-canal,  so  as  to  allow  room  for  the  porcelain  front  D. 
The  porcelain  front  is  ground  in  proper  position  on  this  cap, 


■21-2 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


backed,  attached  with  resin  and  wax,  and  removed  with  the  cap. 
The  cap  is  next  invested  in  plaster  to  the  edge  of  the  collar,  and 
a  little  plaster  placed  on  the  labial  aspect  of  the  porcelain  front 
in  the  form  of  a  matrix,  so  as  to  allow  the   porcelain   to   be 


Fig.  482. 


Fig.  483. 


Fig.  484 


removed  and  replaced.  A  piece  of  heavy  iridio-platinum  plate- 
(E),  No.  16  IT.  S.  standard  gauge,  is  then  shaped  into  the  form 
of  a  half-ring,  with  the  ends  of  the  plate  against  the  backing  of 
the  porcelain  front,  and  of  sufficient  size  to  rest  on  the  flanged 
edge  of  the  cap  when  completed.  On  the  outside  of 
this  half-ring  is  fitted  and  soldered  a  thin  strip  of  gold 
(F)  of  No.  28  IT.  S.  standard  gauge,  which  will  cover 
the  half-ring  and  extend  beyond  its  cervical  margin, 
slightly  overlapping  the  flange  of  the  collar  (G).  This 
forms  a  brace  or  edge  on  the  anchorage  cap  as  it  rests  on 
the  root-cap.  The  half-ring  is  then  fitted  to  the  tooth,  at- 
tached with  wax,  and  removed  with  the  tooth  out  of  the 
plaster  matrix  from  the  root-cap,  invested,  and  securely 
soldered  on  the  inside  to  the  backing  of  the  tooth.  The 
tooth  and  half-ring  are  then  adjusted  to  the  root-cap,  over 
the  post  of  which  the  ring  must  slide  easily  (Fig.  484).  To 
this  ring  the  bridge  is  soldered  the  same  as  to  a  crown. 
"When  the  bridge  is  inserted,  the  cap  for  the  root,  with  the  post, 
is  first  cemented  on  with  oxyphosphate.     After  the  cement  has 


DETACHABLE  AND  REMOVABLE  BRIDGE-WORK.  243 

set,  the  anchorage  ring  is  filled  with  more  cement  and  pressed  into 
position  upon  the  cap  over  the  anchorage  post.  The  surface  of 
the  cement  (H,  Fig.  483)  can  be  protected  by  a  metallic  filling. 

This  form  of  attachment  permits  the  bridge  to  be  easily  re- 
moved by  affording  access  to  the  cement  around  the  pin.  The 
bar  ends  of  the  bridge  are  anchored  in  the  crowns  with  gold  or 
amalgam  fillings,  which  likewise  are  not  difficult  to  remove. 

The  anchorage  cavity  for  a  bar  in  a  gold  molar  crown  for  use 
over  a  tooth  with  a  living  pulp  is  best  made  by  cutting  out  the 
gold  to  the  form  of  the  slot  required,  and  inserting  in  its  place 
a  piece  of  platinum  of  the  shape  of  the  walls  of  the  anchorage 
cavity.  The  crown  is  then  filled  with  investing  material,  and 
the  metal  forming  the  anchorage  cavity  soldered  to  the  crown 
at  the  edges  of  the  cavity. 

DR.    R.    W.    STARR'S    METHODS. 

Dr.  R.  Walter  Starr  gives  the  following  descriptions  of  his 
methods  in  detachable  bridge-work: 

''  The  case  of  Mr.  W.  presented  difficulties  of  an  unusual 
character,  as  may  be  seen  by  inspecting  the  illustration  (Fig.  485), 
which  renders  detailed  description  unnecessary. 

"  It  will  be  observed  that  the  molars  and  the  left  second  bicuspid 
overhang  to  a  degree  that  would  make  the  taking  of  an  accurate 
impression  by  ordinary  methods  well-nigh  impossible.  After  a 
careful  study  of  the  case,  it  was  decided  that  two  separate  pieces 
of  detachable  bridge-work  should  be  attempted,  and,  as  an 
essential  preliminary  step,  the  overhanging  sides  of  the  molars 
and  bicuspids  were  ground  with  engine  corundum-wheels  and 
points  until  those  sides  were  made  much  less  inclined,  when 
plaster  impressions  were  taken,  first  of  one  half,  and  then  of 
the  other  half,  of  the  jaw.  Gold  cap  crowms  were  closely  fitted 
over  the  molars,  left  second  bicuspid,  right  first  bicuspid,  and 
cuspid  stump.  Gold  crowns  were  made  to  telescope  over  all  the 
caps,  which  were  then,  by  means  of  oxyphosphate  cement,  fixed 
firml}-  on  the  teeth.  Suitable  plate  teeth  were  selected,  fitted, 
backed,  and  hard-waxed  in  place  between  the  telescoping 
crowns.  After  hardening  the  wax  with  cold  water  from  a  tooth- 
syringe,  the  pieces  were  carefully  removed,  invested,  and  sol- 
dered.    The  two  completed  bridges  were  easily  replaced  on  or 


^44  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  485. 


Fig.  486. 


DETACHABLE  AND  REMOVABLE  BRIDGE-WORK. 


245 


removed  from  the  supporting  capped  teeth,  and  their  appearance 
when  detached  is  correctly  shown  by  the  illustration,  Fig.  486, 
which  also  shows  the  capped  teeth  and  stumps.  The  figure  like- 
wise shows  the  results  of  the  novel  method  employed  in  crown- 
ing the  incisors.  Gold  collars  were  fitted  tight  on  the  necks  of 
the  incisor  stumps,  and  the  new-style  porcelain  caps  adjusted  in 
the  collars,  and  set  in  the  oxyphosphate  cement  which  had  been 
packed  into  the  collars;  thus  at  the  same  time  fastening  the 
collars  on  the  stumps  and  the  caps  in  the  collars,  as  shown 
completed  in  Figs.  486  and  487. 

Fig.  487. 


"Fig.  487  illustrates  the  finished  crowns  and  bridges,  which 
latter  were  secured  in  position  by  placing  a  small  piece  of  gutta- 
percha in  each  of  the  telescoping  cap  crowns,  which  were  then 
warmed  and  carefully  pressed  in  place, — the  gutta-percha  filling 
only  the  spaces  between  the  flat  tops  of  the  caps  of  the  natural 
teeth  and  cusped  caps  of  the  bridges. 

"  Whenever,  for  repair  or  for  any  other  purpose,  it  shall  lie- 
come  desirable  to  remove  one  of  the  bridges,  that  may  readily 
be  done  by  applying  a  hot  instrument  or  hot  air  to  the  caps  to 
soften  the  gutta-percha  sufficiently  to  permit  the  telescoping 
bridge  to  be  taken  off. 


246 


ARTIFICIAL  CROWN-  AXD  BRIDGE-WORK 


"  A  fall  upper  vulcanite  denture  was  made  to  replace  the  old 
one,  which,  by  improper  occlusion,  had  thrown  the  full  force  of 
mastication  on  the  anterior  teeth  of  the  lower  jaw,  and  produced 
the  destructive  action  that  resulted  in  the  deplorable  loss  of 
tooth-substance  shown  in  Fig.  485."  l 

The  next  case  also  presented  unusual  difficulties.  "  The  forward 
overhang  of  the  inferior  right  second  molar  was  so  excessive  that 
an  impression  could  hardly  be  taken,  until  with  corundum-wheels 
and  points  the  sides  of  the  tooth  had  been  made  parallel,  or 
rather  slightly  tapering  to  form  a  truncated  cone,  with  the  neck 


as  a  base.  The  molar  was  alive  and  sound,  but  the  crown  was 
gone  from  the  pulpless  cuspid,  which  I  suitably  shaped  by  means 
of  my  root-trimmers  (Fig.  488). 

"  An  impression  was  then  taken,  the  cast  from  which  is  illus- 
trated by  Fig.  489.  A  seamless  gold  collar  was,  by  means  of  a 
slightly  tapering  mandrel,  made  to  exactly  fit  the  tapered  natural 
molar,  the  lower  edge  of  the  collar  cut  to  conform  to  the  gin- 
gival margin  ;  a  cap  piece  of  gold  plate  soldered  to  the  top  edge 
of  the  collar,  and  a  hole  drilled  through  the  center  of  the  com- 
pleted cap  (A).  Care  was  taken  to  so  fit  and  proportion  the  cap 
that  it  would  require  finally  pretty  hard  driving  to  send  it  home 

1  Dental  Cosmos,  vol.  xxviii,  No.  1,  page  17. 


DETACHABLE  AND  REMOVABLE  BRIDGE- WORK. 


247 


on  the  tooth;  but  first  there  was  fitted  to  the  cap  a  telescoping 
seamless  collar,  on  which  was  soldered  a  gold  plate,  with  cusps, 
to  form  a  molar  crown  as  shown.  The  molar  was  then  thoroughly 
dried,  slightly  painted  with  Agate  cement,  and  the  cap,  A,  driven 
hard  down  with  a  flat  pine  stick  held  upon  it  and  struck  with  a 
mallet;  the  hole  in  the  cap  enahling  me  to  see  when  the  cap  was 
quite  down.  The  cuspid  was  then  likewise  fitted  with  a  seam- 
less gold  collar,  the  top  edge  of  which  was  given  a  roof-shape,  as 
seen  above  the  root  in  Fig.  489.  A  piece  of  gold  received  a 
corresponding  roof-shape,  had  a  short  section  of  gold  tubing 
soldered  into  it,  and  was  trimmed  to  the  outline  of  the  collar, 
beside  which,  B,  its  form  is  seen,  and  to  which  it  was  subse- 
quently soldered,  after  suitable  investment  to  keep  the  parts  in 


Fig.  490. 


proper  place.  The  root-canal  had  been  previously  prepared  to 
receive  the  tube,  which,  with  its  roofed  cap,  was  with  stick  and 
mallet  driven  hard  down  over  the  root.  A  piece  of  gold  wire 
exactly  fitting  the  tube  had  a  roof-shaped  piece  of  properly 
perforated  gold  plate  slipped  over  it  into  position  on  the  root; 
became  fixed  in  such  relation  by  a  drop  of  melted  hard  wax ; 
was  removed,  invested,  soldered,  and  finished  in  such  shape  that, 
excepting  the  hollowness,  it  looked  like  the  tube  and  cap  B. 

"  The  relations  of  the  occluding  teeth  had,  of  course,  been 
determined  by  an  articulating  model,  and  by  means  of  it  a  series 
of  seamless  gold  collars  and  cusp-crowns  were  adjusted  on  a  thin 
platinum  plate  fitted  on  the  cast  between  the  cuspid  and  second 
molar,  and  the  collars  soldered  to  the  plate  after  investment. 


•248  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

The  truss  thus  formed  received  an  appropriate  finish  by  the 
rounding  and  smoothing  of  its  basal  borders.  A  plain  plate 
cuspid  was  1  tacked  with  gold  plate  and  fitted  on  the  roof-plate,  to 
which,  after  determining  its  proper  occlusion,  it  was  secured  by 
hard  wax;  removed,  invested,  and  soldered.  It  was  then  put 
into  the  tube  on  the  root;  the  telescoping  cap  put  over  the  molar; 
the  truss  put  in  position  in  the  mouth,  and  the  whole  covered 
with  plaster  and  marble-dust,  contained  in  a  suitable  sectional 
impression-tray,  which  enabled  me  to  hold  the  mass  steadily  in 
place  until  the  mixture  was  sufficiently  hard  to  bring  away  cap 
and  truss  and  roof-plate  all  in  proper  position.  A  second  mixture 
of  plaster  and  marble-dust,  and  a  suitable  trimming  of  the  first 
mixture  after  all  was  hard,  sufficed  for  the  soldering  process  that 
resulted  in  the  denture  which,  when  finished,  appeared  as  shown 
detached  at  C,  Fig.  489,  and  mounted  on  the  cast  in  Fig.  490.  It 
went  firmly  to  place  in  the  mouth,  and  yet  was  removable  in  the 
possible  event  of  accident  to  the  denture,  or  for  readjustment  of 
the  cusp-crowTns,  which  latter  could  easily  be  done  by  warming 
the  piece  sufficiently  to  soften  the  gutta-percha,  replacing  the 
denture  on  its  anchorages,  and  directing  the  proper  closure  of 
the  occluding  teeth." 

DR.     PARR'S     METHODS. 

Detachable. — Fig.  491  illustrates  a  method  of  this  style.  The 
teeth  forming  the  abutments  lean  toward  each  other  posteriorly 
and  anteriorly  over  the  space  to  be  bridged,  as  shown  on  the 

Fig.  491. 


original  model,  Fig.  492.  The  bridge  is  supported  by  two 
shoulders  on  the  abutment  crowns,  which  slide  into  grooves 
in  the  dummies  (Fig.  493).  These  supporting  shoulders  and 
slots  are  made  by  shaping  two  pieces  of  platinum  plate  to  the  form 


DETACHABLE  AND  REMOVABLE  BRIDGE-WOltK. 


249 


shown  in  Fig.  494,  so  that  one  shall  telescope  the  other.  The 
inner  one  is  then  invested  on  the  outside  surface  and  filled  in  with 
gold  plate.  The  outer  piece  is  then  filled  inside  with  investing 
material,  and  gold  plate  is  flowed  over  the  outer  surface.  The 
shoulders  are  first  soldered  to  the  crowns,  and  afterward  the 
slots  are  adjusted  to  them  and  soldered  in  position  in  the  bridge. 
Fig.  492.  Fig.  493. 


Fig.  495. 


Fig.  49o  shows  a  bridge  constructed  with  the  attachment 
described  at  one  end  and  a  double  cap  attachment  at  the  other.1 

Removable  Bridge. — In  this  style  the  crowns  forming  the  abut- 
ments are  permanently  cemented  in  position,  each  section  of  the 
bridge  between  them  being  removable.  The  case  illustrated  in 
Fig.  496  will  serve  as  a  type  to  give  the  constructive  details. 
The  cuspid  and  molar  crowns  are  first  formed  in  the  usual  man- 
ner. A  model  from  an  impression  is  then  made  on  which  the 
crowns  will  appear  in  the  same  position  as  in  the  mouth.    A  gold 

•Case  of  Dr.  C.  L.  Alexander,  described  page  27,  Dental  Cosmos,  vol.  xxxiii. 


250  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

and  platinum  bar  (A,  Fig.  497)  is  then  formed  between  the 
cuspid  and  molar.  The  end  for  the  cuspid  is  rounded,  and  that 
for  the  molar  flattened.  This  last  may  be  done  by  hammering 
the  wire  flat  or  by  soldering  a  piece  of  clasp  plate  transversely 
to  it.  The  two  ends  of  the  bar  are  then  fitted  in  sockets  of 
platinum  (B,  B).  The  ends  of  the  bar  should  be  bent  and  the 
platinum  sockets  placed  in  such  a  position  against  the  sides  of 

Fro.  49fi. 


the  crowns  that,  the  bar  can  be  easity  adjusted  and  removed. 
The  sockets  are  next  soldered  to  the  sides  of  the  cuspid  and 
molar  crowns  (A,  A,  Fig.  496),  for  which  purpose  the  sockets 
and  crowns  should  be  removed  and  invested.  The  sockets  are 
held  in  position  when  the  wax  is  melted  out  by  pieces  of  iron 
wire,  one  end  of  which,  covered  with  a  portion  of  the  investing 
material,  is  inserted  in  the  socket,  the  other  end  being  imbedded 
in  the  investment.     Tf  preferred,  the   slot  on  the  side  of  the 

Fig.  497. 


A 
molar  crown  can  be  made  with  a  piece  of  platinum  adapted  over 
the  flat  piece  of  gold  forming  the  end  of  the  bar,  and  then  sol- 
dering the  platinum  to  the  side  of  the  crown,  the  platinum 
being  stiffened  by  flowing  the  solder  over  it.  At  this  point  the 
crowns  and  bar  may  be  adjusted  in  the  mouth,  as  well  as  on  the 
model,  to  insure  accuracy.  A  piece  of  thin  platinum  or  gold  is 
then  perforated  and  slipped  over  the  ends  of  the  bar,  which  is 


DETACHABLE  AND  REMOVABLE  BRIDGE-WORK.  251 

placed  in  position  on  the  crowns,  and  the  platinum  or  gold 
adapted  to  the  form  of  the  attachments,  and  to  the  immediately 
adjacent  surfaces  of  the  crowns.  These  shell  forms  are  made  to 
assure  to  the  ends  of  the  bridge  a  perfect  fit  by  giving  them  the 
shape  of  the  crowns  and  the  attachments  on  the  crowns.  To 
this  bar  the  teeth  constituting  the  bridge  are  fitted  in  their 
respective  positions  and  soldered.  Bending  either  end  of  the 
bar  slightly  (B,  B,  Fig.  496)  or  sawing  a  slit  in  the  cuspid  end 
of  it  (Fig.  428),  afibrds  the  means  of  holding  the  bridge  firmly  in 
position,  although  it  may  be  removed  and  reinserted  at  the  option 
of  its  wearer.     Fig.  498  shows  the  inserted  bridge. 

Fig.  499  shows  another  method  of  forming  a  socket  attach- 
ment. In  the  figure,  the  socket  section  of  the  attachment  is 
seen  projecting  from  the  side  of  the  molar  crown.     The  other 

Fio.  498.  Fig.  499. 


section  consists  of  a  cap  having  a  spring  flange.  The  flange 
enters  the  socket,  which  the  cap  incloses  on  the  top  and  sides. 
The  spring  is  made  by  bending  open  a  little  the  part  of  the 
flange  marked  A. 

This  form  of  attachment  is  constructed  as  follows :  To  make 
the  spring  flange,  two  pieces  of  clasp  or  spring  gold  plate  about 
No.  23  U.  S.  standard  gauge,  one  of  them  one-half  and  the  other 
one-fourth  of  an  inch  long  and  from  one-eighth  to  one-quarter  of 
an  inch  wide,  the  exact  dimensions  being  governed  by  the  case  in 
hand,  are  laid  together,  so  that  one  end  of  the  short  piece  is  nearer 
one  end  of  the  larger  piece  than  the  other.  The  edge  of  the  short 
piece  nearest  the  end  of  the  longer  one  is  then  soldered  to  it  with 
a  hard-flowing  solder,  the  two  being  held  during  the  operation  in 
a  blue  gas  flame  with  tweezers,  and  the  end  is  trimmed  square. 
A  little  whiting  placed  between  the  other  edges  will  prevent  the 
solder  from  flowing  between  or  joining  the  pieces  there.     The 


252 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


short  piece  of  plate  is  to  form  the  spring,  and  is  left  unconnected 
at  one  end  for  that  purpose  (A,  Fig.  500). 

To  Form  the  Socket. — The  spring  flange  is  first  enveloped  once 
around  with  a  thin  piece  of  platinum,  a  little  deeper  than  the 
socket  is  required.     The  platinum  is  then  enveloped  with  one 

thickness  of  coin  gold  plate,  No.  32 
U.  S.  standard  gauge,  about  the  depth 
the  socket  is  to  be,  leaving  a  ledge  of 
the  platinum  projecting.  The  plati- 
num and  gold  are  next  removed  and 
soldered,  by  holding  them  in  a  flame 
and  using  very  little  solder,  of  a  hard- 
flowing  variety,  which  is  placed  upon 
the  ledge.  The  sides  and  ends  of 
the  socket  are  then  filed  level  and  the  socket  given  a  square 
form  (B). 

To  Form  the  Cap. — The  spring  flange  having  been  inserted 
in  the  socket,  two  pieces  of  the  spring  gold  plate  of  the  same 
length  as  the  socket  are  adjusted  along  its  sides,  the  pieces  being 
cut  a  little  wider  than  the  depth  of  the  socket,  so  that  when 
adjusted  they  shall  project  slightly  above  it.  A  piece  of  thin 
platinum  plate  is  then  adapted  to  the  end  of  the  flange,  to  the 
socket,  and  to  the  pieces  of  spring  plate,  first  being  perforated 
to  allow  the  projecting  ends  of  the  latter  to  pass  through  it.  The 
spring  plates  and  the  flange  plate  are  then  cemented  to  the 
platinum  plate  with  wax,  removed  from  the  socket,  invested,, 
and  soldered  (C). 

The  sockets  must  be  so  placed  on  the  crowns  that  the  springs 
at  the  ends  of  the  bridge  shall  enter  them  on  parallel  lines. 
Their  proper  relative  positions  to  secure  this  movement  are 
readily  determined  by  attaching  the  tops  of  the  spring  flanges 
(either  temporarily  or  permanently)  to  the  ends  of  a  piece  of 
wire  of  the  length  of  the  space  to  be  bridged,  which  will  permit 
the  necessary  adjustment.  The  sockets  are  then  soldered  onto 
the  crowns. 

When  the  bridge  teeth  or  dummies  adjoining  the  sockets  have 
been  fitted  in  position,  they  are  withdrawn  with  the  caps  and 
spring  flanges,  and  soldered  to  the  bar,  in  the  manner  described 


DETACHABLE  ASD  REMOVABLE  BRIDGE-WORK. 


253 


at  page  250.  The  gold  caps  forming  the  occluding  surfaces  of 
the  bridge  tooth}  can  usually  he  fitted  over  the  cap.  When  the 
socket  is  attached  lengthwise  from  labial  to  palatal  side  to  a  gold 


Fig.  501. 


Fig.  503. 


crown  as  at  A,  Fig.  496,  the  spring  metal  plate  of  the  flange  is 
best  placed  on  the  side  toward  the  crown. 

In  a  bridge  of  this  style  of  the  anterior  teeth  only, — where  the 


254 


ARTIFICIAL  CROWN-  AXD  BRIDGE-WORK. 


abutments  form  the  extremities  of  the  piece, — the  ends  should 
be  attached  to  the  mesial  sides  of  the  crowns  forming  the  sup- 


Fig.  504. 


ports ;  but  when  it  also  carries  teeth  posterior  to  the  abutment,, 
and  the  sections  of  the  bridge  are  united  together,  the  attach- 


Fig.  505. 


Fig.  506. 


Fig.  507. 


ment  should  be  made  on  the  distal  side,  the  bar  supporting  the- 
anterior  teeth  resting  in  a  slot  formed  on  the  palatal  side  of  the 
abutment  (Fig.  501).  A  shell  crown  on  a  cuspid  can  be  utilized 
as  a  support  for  this  form  of  attachment. 


DETACHABLE  AND  REMOVABLE  BRIDGE-WORK.  255 

The  attachment  described  can  also  be  used  in  combination 
with  removable  plate  bridges. 

Fig.  502  shows  the  cast  of  a  lower  jaw  in  which  only  the  left 
second  molar,  left  cuspid,  and  right  first  bicuspid  remained. 
The  molar  and  bicuspid  were  fitted  with  gold  cap  crowns,  and 
spring  socket  attachments  (Dr.  Parr's  form)  were  soldered  in 
proper  positions  on  the  crowns,  as  illustrated.  The  completed 
denture  in  position  supported  by  the  attachments  is  seen  in  Fig. 
503.     The  under  side  is  shown  in  Fig.  504. 

Fig.  505  represents  the  articulated  cast  of  a  case  in  which  a 
similar  form  of  attachment  and  a  clasp  were  used.  This  is 
illustrated  in  Fig.  506,  which  needs  no  description. 

Fig.  507  shows  the  denture  in  place.  It  was  constructed  of 
vulcanite,  and  made  for  and  placed  in  the  mouth  of  a  patient 
exhibited  at  a  clinic  of  the  Odontological  Society  of  Pennsyl- 
vania, at  Philadelphia,  in  December,  1888. * 

DR.    WATERS'S    METHODS. - 

Dr.  T.  S.  Waters  explains  the  advantages  of  his  removable 
plate  bridge-work  as  follows:  "In  the  system  I  present  the 
denture  is  retained  securely  and  steadily  in  the  mouth,  yet  is 
readily  removed  and  replaced  at  pleasure  by  the  wearer.  The 
pressure  and  strain  are  distributed  properly  over  all  the  struc- 
tures and  tissues  available  for  the  purpose,  and  the  roots  and 
crowns  to  which  the  denture  is  attached  are  so  prepared  that 
there  is  no  place  for  the  lodgment  and  retention  of  food,  and 
when  the  denture  is  removed,  both  it  and  the  mouth  can  be 
thoroughly  cleansed.  Should  the  roots  or  other  tissues  be 
attacked  by  disease,  thus  requiring  treatment,  or  should  repairs 
to  the  mechanism  become  necessary,  the  removable  bridge-work 
offers  facilities  for  those  purposes  not  to  be  found  in  permanent 
dentures." 

Dr.  Waters  thus  describes  the  formation,  combination,  and 
application  of  his  devices  to  cases  of  removable  plate  bridge- 
work  : 

"  My  devices  are  three  in  number,  each  of  which  maybe  used 

1  Dental  Cosmos,  March,  188y. 

-International  Dental  Journal,  April,  1889,  p.  197 


256 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


alone,  or  two  of  them  or  all  three  may  be  combined  and  applied 
in  the  same  case,  as  the  position,  character,  and  relation  of  the 
teeth  and  roots  remaining  in  the  mouth  may  seem  to  indicate. 


Fig.  508. 


"  The  first  is  a  gold  crown  fitted  to  and  sliding  on  a  cap 
attached  permanently  to  the  root  or  natural  crown.  This  cap  is 
made  high  and  has  on  one  side  a  longitudinal  groove.    The  gold 


Fig.  609. 


crown  has  soldered  on  the  inside  a  spring  catch,  which  works  in 
the  groove  on  the  cap,  and  holds  the  crown  firmly  in  its  place. 
The  character  of  the  device  is  seen  in  application  to  the  case 


Fig.  510. 


represented  in  Fig.  508.  Fig.  509  shows  the  denture  in  position. 
Fig.  510  gives  the  lingual  aspect.  It  will  be  readily  seen  that 
under  proper  circumstances  two  or  more  roots  or  teeth  may  be 


DETACHABLE  AND  REMOVABLE  BRIDGE-WORK. 


257 


fitted  with  this  device,  the  gold  crown  may  be  soldered  to  and 
made  a  part  of  the  denture,  making  the  whole  a  piece  of  bridge- 
work  capable  of  being  removed,  cleaned,  and  replaced  at  will. 
The  spring  catch  regulates  the  firmness  of  retention.1 

"  The  next  device  is  the  box  cap  and  split  post ;  the  box  cap 
being  fitted  permanently  to  the  root,  and  the  split  post  being 

Fig.  511. 


Fig.  513. 


soldered  to  the  plate  bearing  the  teeth.  The  box  cap  is  the  usual 
cap,  with  a  box  or  tube  soldered  to  it  and  extending  into  the 
root,  the  cap  end  of  the  tube  being  open.  The  split  post  is  so 
secured  to  the  denture  as  to  slide  snugly  into  this  tube,  the  firm- 
ness of  retention  being  regulated  by  pressing  the  split  slightly 

1  Dr.  Waters  has  patented  this  invention  and  donated  it  to  the  profession. 

18 


258 


ARTIFICIAL  CROWN-   AND  BRIDGE-WORK. 


open  when  necessary.  This  device,  like  the  first,  may,  under 
proper  circumstances,  be  used  by  itself  in  any  case,  as  shown  in 
application  in  Figs.  511,  512,  and  513,  in  which  the  whole  denture 


Fig.  514. 


Fig.  616. 


is  supported  by  box  caps  and  split  posts  adjusted  to  the  roots  of 
the  six  anterior  teeth. 

"  The  third  device  consists  in  soldering  to  the  side  of  the  gold 


DETACHABLE  AND  REMOVABLE  BRIDGE-WORK.  259 

crown  covering  the  natural  tooth  a  split  pin  or  post,  which  is 
inserted  into  the  open  tube  attached  to  the  denture. 

"  As  before  remarked,  these  devices  may  be  used  singly  or  in 
combination  in  any  one  case.  In  one  of  the  dentures  illustrated 
the  box  cap  and  split  post  alone  are  used;  in  another,  the  cap, 
gold  crown,  and  spring  catch  are  used ;  in  the  case  illustrated  in 
Figs.  514,  515,  and  516  the  three  are  applied,  in  which  the  entire 
denture  is  attached  to  and  retained  by  two  cuspids,  a  bicuspid, 
and  a  molar.  In  all  this,  great  care  must  of  course  be  taken  in 
the  preparation  of  the  roots  and  natural  crowns,  to  protect  them 
against  the  action  of  destructive  agents." 


CHAPTER    XII. 

■:  OTABLE   BAR-BEID-:-     3 

.   -      rk  the  bar  is  permanently  attached 

to  the  abutments,  and  spans  the  space  between  them  independent 

:  ::  _         V  _       ration  proper  of  the  denture,  con- 

-  -      .     :   "  teeth     lumnries),  is  formed  with  a  slot,  or 

a  eoonteremnk       -  ich  the  bar  slides  as  the  bridge  is 

Fig.  517. 


!  -  nted  in  Fig.  517,  one  end  of  the  bar  is 

:."ached  to  ih     s jold  molar  crown  and  the  other  end  anchored 
in  the  g  Id  filling.     The  bridge  section  fits  over 

-'_. ■:■       :•.:       -     '.".■>■:.".:-.-'..      7..-.    :.:.->-      :         .-•    :.-.'.    :.    _  "    :.    ';'■'/ 

1  is  capped  with  gold.     A  fiat  bar  of  iridio-platinum, 

"    -  - "      1 .  .      .     and  one-eighth  of  an  inch  wide, — the  width 

.    .  of  1        ase  in  hand, — is  fitted  to  the 

Fthel        -  fitted  in  the  anchorage  cavity  in  the 

:-  I         ■         end  to  the  gold  molar  crown.     A  slot  is 

:L-ri  :::.:.---     bar.  beveled  slightly  toward  the  gam   Fig.  517). 

:   _•  ..te,  about  Xo.  28  gauge,  the  width  of 

I     -  -        -rd  in  the  form  of  a  clamp  to  fit  over  both 

:  and  in  the  slot     The  end  ::  the  bar  is  then 

wn.     The  bar  must  be  placed  far  enough 

space  for  the  artificial  teeth. 


REMOVABLE  EAR-BRLD 


. 


-  .    -  .       -    -  ".  i     ■  \ 

and  removed  fiom  the  bar.     Teeth  and  gold  damp  are  then  in- 

ad  and  soldered  together.   In  investing,,  one  end  of  a  narrow 

Btrij  £  iron  is  inserted  in  the  slot  of  the  gold  clamp,  and 

"tended  into  the  body  of  the  investment,  to  hold 

and  -  the  gold  clamp  in  position,  while  the  gold  solder  is 

flowed   bet  and  the  porcelain  tooth  after  the  wax  is 

When  finished,  the  point  of  the  gold  clamp  is  to  he 

ben  I  inward  to  secure  and  fasten  the  bridge  section  when 

. .    . 

slight!  ~eled  form  given  to  the  slot  in  the  bar.     F  s 


"   • 


.-'::- 


-actional  side  \i- 
-  - 
I»r  'a  method  of  cons 

11 
The  bar  is  formed  as  seen  in 
-  - 


-j 


a     21.     To  the  base 
and  fitted  the  shell  C, 


r„.vl-     :'  i  vrr;   -'..[•.'..■      ::::'.;  r.::".:r!::::   :-r :  ~  :.-:„-.-■. ..  ~:~ 


■ 

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f :- . : :  :  z.     :'  : :   izt-~   ??:   ::■.::•:-.::   :.:.•:.•-: 

:'  -.1     z-   :-a.   -    i~n   : :    :'± 

:  •  -  .-■---- 
i-:ri  :ir-i  :;-  D:  -■•-.--.  i~  Al:-.:i:  :  i:  ■ 
r:-i:.      :;  .:  ?:':i:.:-    I::  iri. 

lit  ~   •ir'.i     :'  i  :.iiT   •  -..=.:  v:    :i-.     -*       _r     ■ 

International   Medical  < 

::-:r:::i   :j  I  -    M    •-     : :  :    -.  a_-.'-    •    -     --"     *.- i 

"  -    -  —  - 


r.  J.  G.  Moray,,  was 

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t-^tzik:  ::  x..-  -  i  i  - 
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; 


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ammsficiai  il-l  i 


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.    -  -  -      .-.  •  _.    .     .-         :     .   - .  -n  "I      -  "'  -  2 

■     7"          •  "_r     : ..:  17.  i  77.  i:    .  -. :  7  "  -.".     .    :  "     n-    =     :  ; : 

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I  •     -    7  ;7t  :':7  ~77 .r  ■  Fig.  of; 

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n      -    .::  -     :  '.  :  -       7 7.-  -  ■•:---      k     _-_    I    .    ' .-    ~   .:.  :7  UC 

t_i  7     :  -     ij         7;-  77.  t  7  : ....  .r..7:>  -7    7:7.777';  i:      - 

7  7     ~  "2  7  .1.1.    12  7     7  7  "    '  -      7  772  -        J-.7     72  l.vrl     7.-     7-77  7  17      SC 

liibi  tike  «»___•  <of  tite-  s&tk-rif  t  :  .7-7"  '-.•77777  7  77. 

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721    T-.-'l         7  -7-7.77 

-.777?  \-y \     _  . 


are  cut  away  mil  ri  Ige fits perfeetlj  \-." 

and  the  soldered  :  -    -    _  -     -  .-.  ~ : ■: pe:  rz i rss . 

and  the wh:.-  sred            an     \-       :-        :   '      -•-   ..' 

>    -       .          . .  ...  -                                   ii.:   "Lie 

=    :■:   '-                    ~  :  t:tV.:  id;  :r:ii-i:  ~                              ; 

obtained.     I"  .-  -            :      ■  \_                  -  ::^il-:-.^        iir 


fk  sa 


Fk    :-i±. 


n 


7::-     :.r 





than  :hv  -  -  ,  _-Ji 

-  -  3  _  ■  bt>| 

then  varnish,  th .  -  -.-.--■ 

and  mar      -dust 
mas-  _    - 


264 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


remove  the  bridge  and  replace  the  arms  in  position  as  marked 
in  the  plaster,  and  retain  them  by  means  of  additional  plaster, 
or  by  steel  springs,  and  solder  them  to  the  crowns,  first  placing 
in  the  joint  sufficient  fluxed  wax  so  that  in  the  process  of  sol- 
dering the  arms  will  be  perfectly  united  to  the  crown,  which 
requires  a  very  small  quantity  of  solder.     The  case  is  now  ready 

to  finish. 

Fig.  527. 


If  the  adjustment  of  arm  and  socket  is  perfect,  the  structure 
will  be  found  to  fit  so  snugly  that  it  is  only  with  considerable 
effort  that  the  bridge  can  be  removed.  With  everything  in 
readiness  for  cementing,  the  crowns  are  quickly  forced  into 
position,  the  bridge  carried  to  place,  and  the  cement  allowed  to 
harden. 

Should  there  be  necessary  in  the  articulation  any  alteration 


REMOVABLE  BAR-BRIDGES.  265 

that  cannot  be  met  by  grinding  off  the  cusps  of  the  antagonizing 
teeth,  the  bridge  can  readily  be  removed  without  disturbing  the 
crowns. 

The  arm  B,  Fig.  524,  is  made  of  a  strip  of  clasp-metal,  Xo. 
16  gauge  in  thickness,  and  of  anv  desired  width  or  length.  The 
strip  is  placed  in  a  slot  like  E,  Fig.  525,  and  the  projecting  end 
hammered  to  form  a  solid  head  as  shown.  A  longer  or  shorter 
arm  may  be  formed  in  the  slot  F,  wherein  the  adjustable  limit, 
G,  may  be  set  to  limit  the  length  of  the  arm  while  the  hammered 
head  is  being  formed.  A  piece  of  20-carat  gold  plate,  or  pref- 
erably clasp-metal  Xo.  33  gauge,  is  cut  to  the  size  and  shape  ot 
Fig.  526,  and  by  means  of  a  former,  K,  Fig.  525,  is  forced  into 
a  suitable  slot.  The  place  of  the  former  K  is  then  taken  by  the 
arm  B,  Fig.  524,  and  the  part  H,  Fig.  525,  bent  and  delicately 
hammered  over  the  head  of  the  arm.  The  socket  so  formed  is 
then  removed,  soldered  from  the  outside,  and  finished  as  at  A, 
to  exactly  fit  the  arm  B,  Fig.  524. 

Figs.  527  and  528  illustrate  a  case  by  Dr.  Parr,  in  which  a 
removable  bar-bridge  plate  was  applied. 


CHAPTER    XIII. 

THE  LOW  BRIDGE. 

Dr.  J.  E.  Low  is  the  reputed  inventor  of  bridge-work  formed 
with  self-cleansing  spaces  and  supported  by  means  of  cemented 
collars  or  collar  crowns.1 

The  following  is  Dr.  Low's  method  of  using  his  step-plug 
crown  (see  page  128)  in  conjunction  with  all-gold  cap  crowns  in 
bridge-work.  Fig.  529  shows  a  case  with  the  prepared  molar 
crowns  and  cuspid  roots.  The  bridge  constructed  according  to 
this  method  is  seen  in  Fig.  530,  and  adjusted  in  position  in  Fig. 
531.  Figs.  532,  533,  and  534  illustrate  a  case  of  four  incisors 
supported  by  two  step-plug  crowns  on  the  cuspids. 

Dr.  Low  gives  the  following  instructions  relating  to  the  con- 
struction of  shell  crowns  or  anchorages  on  cuspids,  to  support  a 
bridge  of  the  four  incisors  in  a  case  such  as  is  shown  in  Fig.  535  : 
"  I  first  measure  the  tooth  with  strips  of  tin,  and  make  the  gold 
bands  and  cut  out  the  outside  lower  portion  of  the  band  before 

1  The  construction  of  bridge-work  supported  by  collars  or  any  form  of  collar 
crowns  cemented  on  teeth  or  roots,  according  to  a  judicial  decision,  is  not  at 
present  free  to  public  use.  The  two  claims  which  reserve  the  use  of  these 
methods  to  the  inventor  as  specified  in  the  letters  patent  granted,  are  as  follows  : 

"  What  I  now  claim  as  new  is  :  1.  The  herein-described  method  of  inserting 
and  supporting  artificial  teeth,  which  consists  in  attaching  said  artificial  teeth  to 
continuous  bands  fitted  and  cemented  to  the  adjoining  permanent  teeth,  whereby 
said  artificial  teeth  are  supported  by  said  permanent  teeth  without  dependence 
upon  the  gum  beneath. 

"  2.  An  artificial  tooth  cut  away  at  the  back,  so  as  not  to  present  any  contact 
with  the  gum  except  along  its  front  lower  edge,  and  supported  by  rigid  attach- 
ment to  one  or  more  adjoining  permanent  teeth,  substantially  as  and  for  the 
purpose  set  forth." 

A  denture  between  two  or  more  teeth  or  roots,  supported  by  such  means  as  bars 
extending  from  it  anchored  into  teeth  or  caps  or  crowns  which  do  not  encircle  the 
teeth  or  roots,  with  the  artificial  teeth  resting  on  or  pressing  into  the  gums  and 
not  formed  with  what  are  termed  and  described  as  self-cleansing  spaces,  and 
removable  bridge-work,  are  not,  in  the  opinion  of  experts,  included  in  the  mean- 
ing or  specifications  of  this  patent. — G.  E. 
266 


THE  LOW  BRIDGE. 


267 


beginning  to  fit.  In  fitting,  as  the  band  is  being  driven  down,  cut 
away  any  of  the  band  that  touches  the  gum  before  all  touches ; 
never  drive  the  band  under  the  gum,  as  inflammation  will  prob- 


Fig.   529. 


ably  follow.  I  mention  this,  as  I  have  seen  many  attempts  to  get 
rid  of  the  bands  by  driving  up  under  the  gums  and  cutting  them 
out  on  the  front,  until  they  are  too  narrow  for  strength.  The 
bands  should  be  heavy  and  strong,  and  the  patient  should  under- 


268 


ARTIFICIAL   CROWN-  AND  BRIDGE-WORK. 


stand  that  if  lie  expects  to  get  rid  of  the  annoyance  of  the  plate 
he  must  sacrifice  his  dislike  to  showing  gold.  After  driving  the 
bands  up  close  to  the  margin  of  the  gums,  as  the  cuspid  teeth 
are  very  tapering,  the  bands  will  have  to  be  taken  in  at  the 

Fig.  532. 


bottom.  To  do  this  I  slit  the  band  about  a  third  of  its  length 
up,  then  place  it  on  the  tooth  again,  lap  it  over  to  bring  it  to  a 
close  fit,  and  then  take  it  off  and  solder.  Continue  taking  it  in 
wherever  it  does  not  perfectly  fit  the  tooth,  and  after  a  good  fit 
Fig.  533.  Fig.  534. 


is  obtained  proceed  with  the  construction  of  the  bridge  by  taking 
an  impression  and  articulation. 

"In  adjusting  the  bridge  when  finished,  first  try  it  on  to  see 
that  it  fits  and  that  the  articulation  is  all  right.  Fig.  536  shows 
the  case  ready  for  adjustment.  Next  dry  the  teeth  upon  which 
the  bands  are  going,  and  then  mix  your  cement.     This  should 


THE  LOW  BRIDGE. 


269 


be  mixed  to  about  the  consistence  of  thick  cream.  It  must  be 
neither  too  thick  nor  too  thin,  or  the  adhesion  will  not  be  strong 
enough  to  hold.     Cover  your  teeth  with  cement,  and  then  the 

Fig.  535. 


inside  of  the  bands.  Place  these  on  the  teeth  and  carefully 
mallet  up  into  position.  For  this  purpose  I  use  a  steel  instru- 
ment with  a  crease  or  groove  in  the  end.  The  teeth  must  be 
kept  dry  after  the  case  is  in  position  until  the  cement  is  well  set. 


Fig.  536. 


After  this  is  done  bevel  the  edges  of  the  bands  and  burnish  close 
to  the  teeth,  and  if  properly  done  they  will  resemble  gold  fillings. 
In  Fig.  537  we  have  the  case  completed.  I  always  impress 
upon  my  patients  the  necessity  of  having  the  case  reset  immedi- 
ately should  it  become  loose,  and  advise  them  to  have  their  cases 
examined  at  least  once  a  vear." 


CHAPTEK    XIV. 

DR.  KNAPP'S  METHODS. 

Dr.  J.  Rollo  Knapp  has  introduced  some  novel  methods  in 
crown-  and  bridge-work,  for  effecting  artistic  results  and  con- 
tinuity of  structure. 

In  crown-work,  Dr.  Knapp  invests  for  soldering  so  that  the 
parts  to  be  united  and  tilled  form  a  miniature  mold.  Into  this 
mold,  at  a  high  heat,  with  a  pointed  flame  from  his  blow-pipe, 
he  flows  solder,  which  fills  the  interstices,  joins  the  parts,  and 
assumes  the  form  of  the  mold.  The  following  is  a  brief  descrip- 
tion of  his  methods : 

Fig.  538.  Fig.  539. 


In  constructing  a  gold  collar  crown  with  porcelain  front,  for 
an  incisor  or  cuspid,  22-carat  The  S.  S.  White  Dental  Mfg.  Co.'s 
collar  gold,  No.  28  standard  gauge,  is  used  for  the  collar,  which  is 
formed  by  adapting  the  gold  to  the  root  by  the  aid  of  pliers.  The 
cap  to  the  band  is  then  made  of  pure  gold,  No.  34  gauge,  and  a 
gold  pin  soldered  in  position  for  the  root-canal.  A  plate  tooth 
is  then  ground  in  proper  position,  backed  with  pure  gold,  and 
fastened  to  the  cap  with  wax.  On  being  removed  from  the  mouth 
after  proper  adjustment,  the  side  and  incisive  portions  of  the  wax, 
including  the  edges  of  the  backing  and  contiguous  portions  of 
the  cap,  are  completely  enveloped  with  pieces  of  pure  gold  No. 
34  gauge  (Figs.  538  and  539).  The  crown  is  then  invested  so 
that  when  the  wax  is  removed  the  backing  on  the  tooth  with  the 
gold  on  the  sides  shall  form  a  small  mold  or  pocket  (Figs.  540 

270 


DR.  KNAPP'S  METHODS. 


271 


and  541\  When  the  investment  is  heated,  the  flame  of  his 
blow-pipe  is  played  over  its  surface  until  the  mass  is  aglow, 
when  the  point  of  the  flame  is  thrown  into  the  mold  by  rapid 
thrusts  until  the  solder  melts  like  wax  and  fills  every  part  of  the 
mold  with  liquid  gold.  This  gives  an  excess  of  gold  which 
affords  ample  facilities  for  contouring  in  the  process  of  finishing 
(Figs.  542  and  543). 


Fig.  540. 


Fig.  541. 


Fig.  542. 


Fig.  543. 


In  constructing  a  bicuspid  crown  with  porcelain  face,  the 
natural  tooth  is  ground  down  to  the  gingival  edge  and  capped 
similar  to  a  cuspid.  A  bicuspid  porcelain  front  is  then  ground 
and  fitted  in  position  (Fig.  544),  and  the  remaining  portion  of 
the  crown  is  shaped  in  wax  to  the  form  required.  A  die  of  the 
grinding-surface  is  then  made  in  metal,  a  cap  stamped  in  pure 


Fig.  544. 


Fig.  545. 


Fig.  546. 


Fig.  547. 


Fig.  548. 


Fig.  549. 


gold,  No.  34  U.  S.  standard  gauge  (Fig.  545),  and  the  cusps 
filled  with  20-carat  gold  solder.  This  cap  is  next  trimmed  (Fig. 
546)  so  as  to  fit  when  placed  in  proper  position  against  the  end 
of  the  porcelain  cusp,  for  which  purpose  sufficient  wax  must  be 
removed.  The  approximal  surfaces  are  enveloped  and  the 
palatal  portion  of  the  collar  protected  with  pieces  of  pure  gold, 
No.  34  standard  gauge,  which  are  slit  to  facilitate  their  adjust- 


272 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


ment  (Fig.  547).  This  leaves  the  palatal  portion  open  when  the 
crown  is  invested  and  the  wax  removed,  which  last  should  be 
done  with  hot  water. 

Fig.  548  shows  the  invested  crown  ready  for  soldering,  in 
which  operation  the  parts  are  filled  in  and  joined  with  20-carat 
gold  solder.  The  result  when  finished  is  a  solid  gold  crown 
with  a  porcelain  front  (Fig.  549). 

All-gold  bicuspid  and  molar  crowns  are  formed  by  Dr.  Knapp 
in  a  similar  manner,  but  as  porcelain  fronts  are  not  used  in 
these  cases,  the  thin  gold  plate  is  placed  entirely  around  the 
labial  aspect  of  the  wax  model.  In  crown-work,  after  the  cap 
has  been  made,  an  impression  is  generally  taken  and  a  plaster 


Fig.  550. 


Fig.  551. 


model  and  articulation  made  to  facilitate  the  subsequent  con- 
struction. 

Dr.  Knapp's  method  of  constructing  bridge-work  is  similar  to 
that  in  general  use  except  in  the  investing  and  the  soldering  to- 
gether of  the  parts,  the  latter  being  done  with  the  blow-pipe  in  a 
manner  similar  to  that  above  described. 

Figs.  550  and  551  illustrate  specimens. 

Dr.  Knapp's  compound  blow-pipe  (Fig.  552)  consists  of  a 
miniature  blow-pipe  in  which  the  ordinary  illuminating  gas 
(carburetted  hydrogen  or  coal  gas)  flame  is  combined  with  a 
current  of  nitrous  oxide  from  a  cylinder  of  the  condensed  gas. 
The  combination  of  these  gases  in  combustion  forms  essentially 


DR.  KNAPP'S  METHODS. 


273 


a  carbo-oxyhydrogen  flame.1  By  means  of  a  yoke  and  set- 
screw,  the  valve  of  the  cylinder  is  connected  with  the  tubes  and 
valves  of  the  blow-pipe,  so  that  the  proportions  of  the  mixture 

Fig.  552. 


1  The  ordinary  compound  oxyhydrogen  blow-pipe  flame  is  produced  by 

2  volumes  of  hydrogen  ;  1  volume  of  oxygen. 
Carburetted  hydrogen  consists  of 

2  volumes  of  hydrogen  ;  1  volume  of  carbon. 
And  nitrous  oxide  of 

2  volumes  of  hydrogen  ;  1  volume  of  oxygen. 
Consequently  Knapp's  blow-pipe  flame  is  produced  by  a  mechanical  mixture  of 
2  volumes  of  hydrogen  ;  1  volume  of  oxygen  ;  1  volume  of  carbon. 

19 


074  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

of  nitrous  oxide  and  the  illuminating  gases  are  under  perfect 
control.  The  flame-jet  can  be  diminished  to  half  an  inch  in 
length,  and  at  that  size  will  melt  a  small  piece  of  gold  plate. 

Where  illuminating  gas  is  not  available,  an  apparatus  termed 
a  carburetter  can  be  used,  which  supplies  the  deficiency  in  a 
simple  manner  by  vaporizing  naphtha. 

This  blow-pipe  is  useful  for  many  purposes  in  the  laboratory 
of  the  present  time,  especially  in  forming  solid  gold  backings  to 
dummies  for  bridge-work,  strengthening  seamless  gold  crowns, 
and  forming  solid  gold  crowns. 

Dr.  Knapp  has  exhibited  to  the  profession  some  very  fine 
specimens  of  crown-  and  bridge-work,  and  presented  much  that 
is  novel  and  interesting,  as  well  as  encouraging  to  the  artistic 
element  of  prosthetic  dentistry.  The  real  value  of  processes  or 
methods,  however,  depends  on  their  practicability.  Therefore, 
in  contemplating  that  which  is  novel  and  beautiful  in  connection 
with  dental  art,  we  must  be  governed  by  this  fact  in  estimating 
its  value.  Judged  from  this  standpoint,  Dr.  Knapp's  special 
methods,  while  admitting  of  the  highest  artistic  results,  embrace 
some  processes  which,  on  account  of  their  intricacy,  are  not 
likely  to  be  generally  adopted  in  practice. 


CHAPTE  E,    XV. 

DR.  MELOTTE'S  METHOD. 

Dr.  G.  W.  Melotte  describes  the  construction  of  a  bridge 
supported  by  a  gold  crown,  and  a  shell  or  partial  gold  crown, 
and  the  use  of  his  invention,  "moldine,"  in  connection  with 
fusible  metal  in  crown-  and  bridge-work,  as  follows : x 

"  Fig.  553  illustrates  a  case  for  the  supply  of  a  lateral  and  a 
bicuspid.  In  this  instance  the  cuspid  could  be  cut  off,  and  the 
root  collared  and  capped  in  combination  with  a  pin  entering  the 
enlarged  root-canal;  but  as  there  may  be  grounds  for  objection 
to  cutting  off  sound  teeth,  I  ob- 
viate  the  necessity  by  cutting  a 
shoulder  on  the  lingual  portion 
of  the  cuspid,  and  suitably 
shaping  its  sides  to  permit  a  close 
fitting  of  the  collar  just  under 

the  free  margin  of  the  gum.  A  narrow  strip  of  pure  pattern 
tin,  bent  tight  around  the  tooth-neck,  and  cut  through  with  a 
knife  at  the  lap  on  the  labial  surface,  will  serve  as  a  measure  for 
the  length  of  a  strip  of  22-carat  gold  plate,  No.  29  thick,  and  as 
wide  as  the  length  of  the  distal  side  of  the  cuspid.  The  ends  of 
the  gold  are  then  squared,  and  with  round-nosed  pliers  brought 
evenly  together,  to  be  held  in  flush  contact  by  the  soldering- 
clamp  as  shown  in  Fig.  554.  The  soldered  collar,  with  its  joint 
side  inward,  is  then  adjusted  on  the  tooth  as  accurately  as  pos- 
sible, giving  slight  blows  with  a  mallet  until  the  collar  touches 
the  gum,  when  it  should  be  marked  to  indicate  the  necessary 
trimming  to  conform  it  to  the  gum  contour.  After  it  has  been 
thus  trimmed,  the  edges  beveled,  the  labial  part  swelled  with 
contouring  pliers,  and  the  lingual  part  cut  down  to  about  one- 
tenth  of  an  inch  in  width,  the  collar  is  again  driven  on,  and  will 

1  Dental  Cos)nos,  vol.  xxviii,  No.  12,  page;  745. 

275 


276 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


appear  as  seen  in  Fig.  553.  A  stump  corundum-wheel  is  then 
used  to  grind  a  shoulder  on  the  lingual  surface  of  the  tooth, 
grinding  also  the  edges  of  the  collar  flush  with  the  shoulder. 
The  collar  is  again  removed,  and  a  piece  of  thin  platinum  plate, 
about  No.  32,  sufficient  to  cover  the  lingual  surface  of  the  tooth, 
is  caught  on  the  lingual  edge  of  the  collar  by  the  least  bit  of 
solder,  and  all  put  in  place  on  the  cuspid  (Fig.  555).  The 
platinum  should  now  be  burnished  on  to  the  shoulder,  and  over 
the  tooth  and  collar  to  the  extent  shown  by  the  lines  in  Fig.  555. 

Fig.  554. 


Fig.  556.     Fig.  556. 


Fig.  557. 


After  trimming  to  those  lines,  and  careful  replacement  and  bur- 
nishing on  the  tooth,  the  collar  and  half-cap  are  removed,  filled 
with  wet  plaster  and  marble-dust,  and  the  platinum  soldered  to 
the  gold.  It  is  then  placed  on  the  tooth,  burnished  into  all  the 
inequalities  of  the  tooth,  very  carefully  removed,  invested,  and 

enough  solder  flowed  over  the 
platinum  to  cover  and  give  it 
strength.  Fig.  556  shows  it 
complete  on  the  cuspid. 

"  I  have  feared  that  a  detailed 

statement  would  imply  a  long 

and  tedious  process,  but  I  have 

often  made  such  collars  in  less  than  an  hour,  and  in  any  case 

time  must  be  made  subservient  to  exactness  of  fit  and  adaptation 

to  the  end  in  view. 

"  In  the  preparation  for  fitting  a  collar  on  the  first  molar  (Fig. 
553),  I  should  have  wedged  or  otherwise  separated  it  from  the 
second  molar,  so  that  a  piece  of  sheet  brass  might  be  put  in 
place,  as  shown  by  Fig.  557,  and  an  impression  taken  in  plaster, 


DR.  MELOTTE'S  METHOD.  277 

which  if  allowed  to  get  hard  would  bring  away  the  metal.  If 
not,  it  could  be  replaced  in  the  plaster.  Melted  fusible  metal. 
when  near  the  cooling-point,  is  then  poured  into  the  impression, 
and  when  cold  will  allow  the  safe  removal  of  both  the  plaster 
and  the  metal  strip.  On  this  metal  model  a  collar  can  be  formed 
that  will  accurately  fit  the  molar,  as  seen  in  Fig.  553.  If  the 
molar  has  no  antagonist,  a  cap  may  at  once  be  struck  up  on  the 
model;  but  if  there  be  an  antagonist  the  cusps  of  the  natural 
molar  should  be  removed  by  grinding  at  points  where  the 
occluding  tooth  will  admit  of  sufficient  thickness  of  the  gold 
cap.  An  exact  copy  of  the  ground  cusps  can  then  be  made  in 
less  than  five  minutes,  by  the  use  of  moldine  with  its  acces- 
sories, and  the  process  is  as  follows :  Make  the  tooth  perfectly 
dry.  Put  the  collar  on  it.  Nearly  fill  the  cup  with  moldine, 
and  coat  it  with  soapstone  powder.  Press  the  compound  on  the 
tooth  and  collar  firmly  to  about  one-fourth  the  depth  of  the 
tooth.  Carefully  remove  the  cup ;  trim  ofT  any  overhanging 
material,  and  place  the  rubber  ring  over  the  cup  to  about  one- 
half  the  depth  of  the  ring.  Melt  the  fusible  metal  and  pour  it 
as  cool  as  it  will  run  from  the  iron  ladle.  As  soon  as  the  metal 
is  hard,  remove  it  with  the  ring,  taking  care  not  to  impair  the 
impression,  which  can  be  used  again  if  the  die  is  found  imperfect 
or  gets  injured  in  use.  Place  the  die  and  ring  in  cold  water,  to 
remain  until  quite  cooled.  While  the  die  is  wet  and  held  over  a 
basin  of  water,  pour  into  the  ring  fusible  metal  which  has  been 
stirred  until  it  begins  to  granulate,  and  quickly  immerse  all  in 
the  water.  The  die  and  counter-die  should  separate  readily  by 
tapping  them  with  a  hammer,  but  if  they  stick  others  can  be 
quicklv  made  from  the  same  impression  by  the  same  method, 
using  more  care.  With  this  die  and  its  counter-die,  a  piece  of 
No.  29  or  30  gold  plate  is  swaged  to  fit  perfectly  the  cusps  and 
collar,  which,  when  removed,  can  be  held  to  its  place  on  the  cap 
by  the  soldering-clamp,  using  spring  pressure  enough  merely  to 
hold  them  together  for  careful  soldering  with  the  pointed  flame 
so  as  not  to  unsolder  the  collar.  The  seamless  collars  are  excel- 
lent when  care  is  used  in  selecting  the  proper  size,  as  directed 
on  the  diagram  (see  page  290). 

"  The  caps  being  in  place  on  the  cuspid  and  molar,  an  impres- 


278  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

sion  is  taken  with  plaster;  the  caps  accurately  set  in  the  impres- 
sion, and  hard  wax  melted  with  a  hot  spatula  around  the  edges 
of  the  caps.  The  impression  is  then  thoroughly  coated  with 
sandarac  varnish,  after  which  it  is  dipped  for  a  moment  in  water, 
and  tilled  with  a  wet  mixture  of  one  part  marble-dust  with  two 
parts  of  plaster;  using  great  care  to  perfectly  fill  the  caps  and 
molds  of  the  teeth.  Wait  until  this  mixture  has  become  quite 
hard:  remove  the  cup,  and  with  a  suitable  knife  chip  off  the 
plaster  without  marring  the  cast :    secure  a  good  articulating 

Fig.  558. 


impression  and  transfer  it  to  the  cast  to  obtain  an  exact  repro- 
duction of  the  relative  occlusions  of  all  the  teeth  involved. 
With  such  an  articulation  in  hand,  and  with  the  means  already 
described  for  swaging  gold  or  platinum  plate  to  fit  the  cusps  and 
articulating  surfaces  of  either  the  natural  or  artificial  teeth,  it 
should  be  within  the  capacity  of  any  competent  dentist  to  com- 
plete a  suitable  bridge ;  although  there  are  practical  points  that 
can  only  be  imparted  by  clinical  instruction  and  actual  demon- 
stration in  the  mouth.  Such  a  bridge  is  shown  in  position  by 
Fig.  558." 


CHAPTER    XVI. 

PARTIAL  CAP  AND  PIN-BRIDGE  METHODS. 

Dr.  W.  F.  Litch's  processes  in  this  style  of  work  have  for 
special  cases  many  decided  advantages,  and  are  thus  described 
by  him : l 

"Fig.  559  represents  a  typical  case,  in  which  a  lateral  incisor 
(crown  and  root)  has  been  lost,  the  cuspid  and  front  incisor,  fully 
vitalized,  and  without  approximal  carious  cavities,  remaining  in 
position. 

"  To  Make  a  Pin  and  Plate  Bridge.  —  1.  Take  in  plaster  an 
accurate  impression  of  the  cuspid  and  incisor  and  the  interspace. 
From  this  obtain  a  plaster  model  of  the  parts. 

Fig.  -350. 


"  2.  Make  from  pure  gold,  rolled  to  the  thinness  of  No.  26, 
standard  gauge,  base-plates,  to  be  carefully  adjusted  to  the  palato- 
approximal  surfaces  of  the  cuspid  and  incisor.  These  can  be 
made  by  swaging  on  dies  and  counter-dies  obtained  from  the 
model,  but  more  conveniently  by  bending  the  gold  into  shape 
upon  the  plaster  model  and  pressing  and  burnishing  it  into 
perfect  adaptation  upon  the  natural  teeth. 

"3.  Select  a  plain  plate  porcelain  tooth  of  suitable  length, 
shape,  and  shade,  and  wide  enough  to  tit  easily  into  the  inter- 
space.    Let  the  neck  of  the  tooth  rest  lightly  upon  the  gum. 

1  Dental  Cosmos,  vol.  xxviii,  No.  3. 

279 


■2st)  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

"  4.  With  pure  gold  or  platinum  make  a  backing  for  the  por- 
celain tooth. 

"  5.  Place  the  tooth  thus  prepared  and  the  base-plates  already 
made  upon  the  cast,  and  accurately  adjust  the  approximal  edges 
of  the  base-plates  to  the  backing  of  the  porcelain  tooth  in  situ 
upon  the  cast. 

"  6.  When  this  adjustment  is  made,  cement  together  the  base- 
plates and  backing  with  a  brittle,  resinous  cement  (resin,  two 
parts;  wax,  one  part;  or  sealing-wax  will  answer),  and  before 
the  cement  has  fully  hardened  remove  from  the  cast  to  position 
in  the  mouth,  perfecting  the  final  adjustment  there.  By  this 
method  much  greater  accuracy  of  adaptation  is  obtained,  as  the 
lines  of  length,  width,  and  contour  are  too  fine  to  be  repro- 
duced with  absolute  fidelity  in  a  plaster  model.  In  this  part  of 
the  process  too  much  care  cannot  be  taken  to  have  each  piece  of 
the  appliance  fitted  with  absolute  accuracy  to  the  surface  for 
which  it  is  designed.  When  this  has  been  accomplished,  throw 
upon  the  yet  more  or  less  plastic  cement  a  stream  of  ice-cold 
water  from  an  office  syringe ;  this  renders  the  cement  perfectly 
brittle  and  incapable  of  bending.  This  done,  immediately 
remove  from  the  mouth  and  invest  in  a  mixture  of  equal  parts 
of  marble-dust  and  plaster  of  Paris. 

"  7.  After  the  investment  has  firmly  set,  solder  the  base- 
plates to  the  backing,  and  the  backing  to  the  platinum  pins  of 
the  porcelain  tooth,  using  as  a  solder  20-carat  gold.  Thus 
joined,  the  appliance  will  present  the  appearance  shown  in  Fig. 
563, — A  representing  the  base-plate  for  the  cuspid;  B,  the  base- 
plate for  the  incisor;  C,  the  porcelain  tooth  with  its  platinum 
backing;  I),  the  points  of  union  between  the  base-plates  and 
backing.  At  these  points  the  greatest  strength  is  required,  and 
it  is  important  that  here  a  large  amount  of  the  solder  should  be 
placed.  The  porcelain  tooth  being  usually  thinner  than  the 
natural  teeth,  there  is  nearly  always  an  angle  or  depression  at 
the  points  indicated,  in  which  the  thickness  of  the  gold  can  be 
considerably  increased  without  interfering  with  occlusion. 

"  8.  For  the  purpose  of  attaching  the  denture  as  thus  far  con- 
structed, drill  a  small  cylindrical  opening  through  the  palatal 
surface  of  the  enamel  of  the  cuspid  and  incisor  respectively. 


PARTIAL  CAP  AND  PIN-BRIDGE  METHODS. 


281 


These  openings  should  usually  be  placed  about  as  indicated  in 
Fig.  562,  at  C,  D.     Sometimes,  owing  to  a  close  occlusion  or  to 


Fig.  560. 


Fig  561. 


the  contour  of  the  tooth,  it  is  desirable  that  they  should  be  located 
a  trifle  nearer  the  neck  of  the  tooth.     Each  opening  should  be 


Fig.  562. 


well  undercut,  but  must  not  encroach  upon  the  dentine  far 
enough  to  endanger  the  pulp.  In  size  the  openings  need  not 
be  larger  than  will* admit  a  platinum  pin-head,  in  diameter  cor- 
responding to  No.  13,  standard  gauge,  with  a  shank  of  No.  18, 


standard  gauge.  Into  each  of  these  openings  must  be  fitted  a 
platinum  pin  of  the  size  indicated.  The  head  of  each  pin  must 
be  made  thin  and  perfectly  flat  both  upon  its  upper  and  under 
surfac*  is.1 

1  Practical  experience  in  the  use  of  attachments  of  this  form  shows  that  two  pins 
in  one,  if  not  in  each  of  the  caps,  are  necessary. — G.  E. 


282  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

"  9.  In  each  of  the  base-plates  make  an  opening  correspond- 
ing in  position  to  those  in  the  natural  teeth.  Pass  through  these 
openings  and  cement  in  them  the  free  ends  of  the  platinum  pins. 
While  the  cement  is  yet  plastic,  place  the  denture  in  position  in 
the  mouth,  carefully  pressing  the  pin-heads  into  the  openings 
made  for  them,  and  burnishing  the  base-plates  into  perfect 
contact  with  the  palatal  surfaces  of  the  teeth;  chill  the  cement, 
remove  and  invest  as  before,  and  with  20-carat  gold  solder  the 
pins  to  the  base-plates,  flowing  upon  them  and  the  backing  as 
much  of  the  solder  as  may  be  necessary  to  give  them  the  desired 
thickness  and  rigidity ;  the  amount  admissible  largely  depend- 
ing upon  the  nature  of  the  occlusion ;  a  central  thickness  of 
about  No.  21,  standard  gauge,  being  all  that  is  really  requisite 
for  strength,  while  the  edges  can  be  made  much  thinner. 

"Fig.  560  represents  the  appliance  without  the  pin.  A  is  the 
porcelain  tooth  and  backing;  E,  the  base-plates;  C  and  F,  the 
openings  for  the  pins. 

"  Fig.  561  represents  the  appliance  completed  with  the  pins  in 
position. 

"  Fig.  562  represents  the  natural  teeth  and  interspace  B,  with 
openings  for  retaining-pins,  C,  D. 

"  Fig.  563,  already  described,  represents  the  appearance  pre- 
sented when  the  bridge  is  cemented  in  position. 

"  To  Attach  the  Bridge. — To  attach  the  bridge  the  best  attain- 
able oxyphosphate  cement  should  be  used.  It  is  desirable  that  it 
should  set  slowly.  Thoroughly  dry  the  teeth  and  denture;  mix 
the  cement  to  as  thick  a  consistence  as  is  compatible  with  per- 
fect plasticity.  A  thick,  viscid,  semi-fluid  mass  is  what  is  re- 
quired. "With  suitable  instruments,  swiftly  but  carefully  place 
the  cement  around  the  head  and  shank  of  each  platinum  pin, 
and  also  in  the  openings  in  the  natural  teeth.  This  care  is 
necessary  in  order  to  exclude  all  air-bubbles  and  thoroughly 
engage  the  pin-heads  in  the  cement.  They  furnish  ample 
retaining  surface,  but  none  to  spare.  In  packing  the  cement 
around  the  pins,  the  under  surface  of  the  base-plates  should  at 
the  same  time  be  covered. 

"  The  above  details  being  perfected,  the  denture  is  at  once 
carried  to  position,  and  with  broad-pointed,  serrated  instruments 


PARTIAL  CAP  AND  PIN-BRIDGE  METHODS.  283 

pressed  firmly  into  place,  the  excess  of  cement,  if  of  the  proper 
consistence,  freely  oozing  at  all  margins. 

"  Application  to  Pulpless  Teeth. — In  the  above  description  the 
vitality  of  the  pulps  of  the  cuspid  and  incisor  has  been  assumed; 
but,  as  can  readily  be  understood,  the  pin  and  plate  bridge  can 
be  even  more  easily  and  securely  placed  when  one  or  both 
pulps  are  devitalized,  for  the  reason  that,  the  pulp-chamber  being 
empt}T,  the  pin-holes  in  that  tooth  can  be  made  as  much  larger 
and  deeper  as  may  be  deemed  desirable,  the  size  of  the  pin  being, 
of  course,  correspondingly  increased.  In  a  devitalized  tooth, 
too,  the  base-plates  can  be  sunk  into  the  palatal  surface  when 
they  interfere  with  occlusions,  as  sometimes  happens  when  the 
antagonism  of  the  lower  teeth  is  very  close  and  the  overlap  is 
considerable. 

"  Ordinarily,  however,  such  interference  is  inconsiderable,  and 
the  difficulty  can  always  be  overcome  either  in  devitalized  teeth 
by  the  expedient  just  suggested,  or  by  carrying  the  base-plates 
as  far  away  from  the  cutting-edge  as  practicable,  at  the  same 
time  making  them  at  the  point  of  contact  as  thin  as  is  consistent 
with  strength;  finally,  if  necessary,  removing  a  slight  portion 
of  the  cutting-edge  of  the  occluding  lower  tooth.     .     .     . 

"  As  a  rule  the  writer  has  confined  the  use  of  this  form  of 
bridge  to  cases  in  which  only  a  single  incisor  is  missing,  but  he 
has  successfully  attached  a  front  and  lateral  incisor  to  a  cuspid 
and  the  remaining  front  incisor.  Where  an  unusual  strain 
is  to  be  expected  the  retaining-pins  and  pin-holes  should  when 
practicable  be  made  correspondingly  large,  or  two  smaller  pins 
may  be  anchored  in  one  tooth,  which  latter  plan  gives  very  great 
resisting  power. 

"  Pin  and  Plate  Attachments  to  Bicuspids. — Although  chiefly 
applicable  to  the  incisors,  the  pin  and  plate  attachment  may  be 
successfully  combined  with  crown-  or  bar-bridges  for  molars 
and  bicuspids. 

"  Fig.  564  represents  a  practical  case  in  which  the  upper  third 
molar  and  the  first  bicuspid  (both  without  antagonizing  teeth) 
were  utilized  for  the  attachment  of  a  bridge  made  of  gold 
crowns  with  porcelain  facings,  to  supply  the  loss  of  the  interven- 
ing teeth. 


284 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


"  Fig.  565  represents  the  case  as  prepared  for  the  bridge.     A, 
the  inner  cusp  of  the  bicuspid  cut  down  to  allow  the  placing  of 


Fig.   564. 


a  sufficiently  thick  crown-plate;  B,  a  cylindrical  undercut  open- 
ing between  the  cusps  for  a  retaining-pin ;  C,  the  third  molar, 


Fig.  565. 


made  uniform  in  size  from  neck  to  grinding-surface,  the  latter 
also  being  considerably  retrenched ;   D,  the    crown-plate    of  a 

Fig.  566. 


partial  cap,  made  of  pure  gold,  soldered  with  20-carat  gold,  and 
so  constructed  as  to  cover  every  portion  of  the  tooth  except  its 


PARTIAL  CAP  AND  PIN-BRIDGE  METHODS. 


285 


buccal  surface,  the  free  edge  passing  up  under  the  gum  ;  E,  a 
retaining-pin  adapted  to  the  opening  B ;  F,  the  gold  cap  for  the 
molar. 

"  Fig.  566  represents  the  bridge  anchored  in  position  with 
oxyphosphate  cement. 

"  In  the  above  case  it  will  be  observed  that  there  is  a  con- 

Fig.  567. 


eiderable  space  between  the  bicuspid  and  cuspid.  This  made  it 
readily  practicable  to  give  so  considerable  a  thickness  to  the 
mesial  wall  of  the  partial  cap  as  to  hold  it  securely  against  the 
side  of  the  tooth.  Had  the  space  been  less,  contact  with  the 
cuspid  would  have  afforded  the  desired  security. 

"  Fig.  567  represents  another  case  in  which  a  bridge  was  at- 

Fig.  568. 


tached  by  a  bar,  partial  cap,  aud  retaining-pin.  A  is  an  upper 
second  bicuspid  (without  antagonist);  B,  its  inner  cusp,  cut 
down ;  C,  opening  for  retaining-pin ;  D,  second  molar,  with 
slot  for  bar;  E,  cuspid;  F  represents  the  partial  facing;  G,  the 
retaining-pin ;  H,  a  molar  crown  of  gold,  with  porcelain  front ; 
I,  a  platinum  bar  attached  to  the  crown  (H)  and  made  to  fit  into 


286  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

a  slot  (at  D);  J,  a  plain  plate  cuspid,  heavily  backed  and  strongly 
soldered  to  the  partial  cap,  but  left  without  attachment  to  or 
contact  with  the  cuspid. 

"  Fig.  568  shows  the  bridge  anchored  in  position. 

"  This  case,  after  two  years  of  wear,  is  still  in  perfect  condition 
and  doing  good  service.  As  it  was  possible  to  keep  the  gold  attach- 
ments, backings,  etc.,  out  of  sight,  the  appearance  presented  is 
very  natural. 

"  The  absence  of  antagonizing  teeth  for  the  bicuspids  in  each 
of  these  cases  was  a  favorable  condition,  as  a  considerable  thick- 
ness could  be  given  to  the  crown-plate  without  any  interference 
with  occlusion.  When  the  conditions  are  not  so  favorable, 
cutting  down  the  inner  cusp  to  the  required  extent  and  sinking 
the  opening  for  the  retaining-pin  to  the  necessary  depth  are  pro- 
cesses certainly  to  be,  as  a  rule,  preferred  to  the  entire  removal 
of  the  crown  for  the  purpose  of  ferruling  the  root  for  the  mount- 
ing of  a  crown  of  gold  and  porcelain, — a  procedure,  however, 
not  by  any  means  to  be  indiscriminately  denounced,  for  in  many 
cases  it  is  in  the  highest  degree  advisable. 

"  There  is  this  fact  to  be  considered  in  regard  to  the  use  of  the 
partial  caps  here  figured, — that  many  patients  can  be  induced  to 
consent  to  their  employment  who  would  refuse  to  submit  to 
more  radical  measures,  and  thus,  even  when  the  latter  would  be 
advisable,  the  former  may  be  employed  as  a  compromise,  or  even 
as  a  temporary  expedient.  Having  once  tested  the  advantage  of 
a  well-fitting  bridge,  the  wearer  is  much  more  likely  to  consent 
to  whatever  measures  are  necessary  to  give  it  security  and  per- 
manence." 


CHAPTER    XVII. 

THE  MANDREL  SYSTEM. 

In  all  styles  of  collar  crowns  the  shaping  and  adapting  of  the 
collar  is  usually  found  by  many  dentists  to  be  the  most  difficult 
part  in  their  construction.  To  facilitate  its  performance  the 
"  Mandrel  System"  was  introduced  by  The  S.  S.  "White  Dental 
Manufacturing  Co.  The  following  is  a  revised  description  taken 
from  an  article  on  the  subject:1 

"  An  examination  of  a  large  number  of  human  teeth  shows 
that,  no  matter  how  great  differences  may  exist  in  the  apparent 
shapes  of  the  crowns  of  individual  teeth  of  a  given  class,  there 
is  a  remarkable  uniformity  in  the  configuration  of  their  necks. 
That  is,  the  necks  of  upper  cuspids,  for  instance,  were  found  to 
have  a  fixed  type,  from  which  the  variations  were  very  slight  as 
to  shape,  though  there  appeared  to  be  no  exact  standard  of  size. 
So  of  the  other  classes,  with  the  single  exception  of  the  superior 
molars,  in  which  two  distinct  forms  were  found,  the  first  being 
those  in  which  the  buccal  roots  were  wider  than  the  palatal ; 
the  second,  those  in  which  the  reverse  condition  was  found,  the 
single  palatal  root  being  wider  at  its  junction  with  the  crown 
than  the  two  buccal  roots.  The  occurrence  of  roots  of  the 
second  class  being  rather  exceptional,  the  first  class  was  accepted 
as  the  type. 

"  The  configuration  of  the  necks  of  all  the  teeth  having  been 
determined,  a  set  of  mandrels  for  shaping  collars  to  fit  them  was 
devised.  The  set  (Fig.  569)  consists  of  seven  mandrels,  six  of 
which  are  double  end.  Their  shapes  are  modeled  upon  the 
general  typal  forms  of  the  necks  of  the  teeth  which  they  repre- 
sent, and  they  are  made  tapering  to  provide  for  all  required 
variations  in  size.     The  illustrations  are  about  two-thirds  actual 

^Dental  Cosmos,  vol.  xxviii,  No.  fc<. 

287 


Fig.  569. 
FOR  SHAPING  SEAMLESS  TOOTH-ROOT  COLLARS. 


No.  1. 


No.  2. 


No.  3. 


No.  4. 


Ho.  5. 


No.  6. 


No.  7. 


288 


THE  MANDREL  SYSTEM.  L>s«,i 

size,  the  longest  instruments  being  nine  inches  in  length.  The 
cross-sections  show  the  shapes  and  proportionate  sizes  at  the 
greatest  and  least  diameters.  The  long  taper  permits  the  most 
minutely  accurate  adjustment  of  the  collars. 

"  No.  1  is  a  double-end  mandrel,  for  superior  molars,  right  and 
left ;  Xo.  2  is  a  single  mandrel,  for  superior  bicuspids,  right  and 
left;  Xo.  3  is  double-end,  for  superior  cuspids,  right  and  left; 
No.  4,  double-end,  for  superior  centrals,  right  and  left ;  Xo.  5, 
double-end,  for  inferior  molars,  right  and  left ;  Xo.  6,  double-end, 
for  the  inferior  centrals,  laterals,  cuspids,  and  first  bicuspids,  right 
and  left;  Xo.  7,  double-end,  one  end  for  the  superior  lateral 
incisors,  the  other  for  those  bicuspids  in  which  a  bifurcation  of 
the  roots,  or  a  tendency  in  that  direction,  extends  across  the  neck 
to  the  crown  in  the  form  of  a  depression  on  one  or  both  approx- 
imal  surfaces.  The  foregoing  scheme  comprehends  all  the  teeth 
of  the  permanent  set  except  the  second  inferior  bicuspids.  The 
necks  of  these  approximate  those  of  the  superior  central  incisors 
so  closely  in  shape  that  it  was  deemed  inexpedient  to  make  a 
separate  mandrel,  as  the  Xo.  4  mandrel  will  serve  for  both. 

"  The  collars  or  bands  are  made  seamless,  of  Xo.  30  (Ameri- 
can gauge)  gold  plate,  22  carats  fine.  Fifteen  sizes,  each  of 
three  widths  (y1^,  y2^,  and  T37  inch)  are  made  (Fig.  571),  which  it 
is  believed  will  cover  all  requirements.  These  collars,  although 
devised  as  a  part  of  the  system,  can  be  used  in  all  methods  of 
crown-  and  bridge-work  which  require  bands,  and  possess  many 
advantages  over  any  others.  They  are  really  labor-saving 
devices,  as  their  use  saves  the  time  and  trouble  of  making,  and 
there  is  no  danger  of  their  coming  unsoldered  when  the  pins  or 
the  backing  of  the  crown  are  being  soldered;  and  there  are  no 
hard  spots  to  give  trouble  in  burnishing,  as,  for  instance,  close  to 
the  root,  after  the  collar  has  been  shaped  and  placed  in  position, 
the  whole  surface  being  uniformly  soft. 

"  The  seamless  collars  are  also  especially  adapted  to  removable 
or  detachable  bridge-work.  They  are  so  constructed  that  Xos. 
1, 16,  and  31  exactly  fit  into  or  telescope  with  Xos.  2, 17,  and  32, 
and  so  on  through  the  entire  set,  each  collar  fits  into  the  series 
next  higher :  so  that  a  root  may  be  banded  with  one  size  and 
the  size  next  larger  used  to  form  the  tribe  for  the  telescoping 

20 


290  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

crown.  When  desirable,  the  '  seamless'  collar  can  be  strength- 
ened, after  it  has  been  adapted  to  the  conformation  of  the  crown 
so  as  to  slide  freely  over  it,  by  investing  and  flowing  solder  over 
the  outer  surface ;  or,  still  better,  by  adapting  the  next  larger 
size  of  collar  to  exactly  fit  around  the  first,  and  then  investing 
the  two  and  soldering  them  together.     The  advantages  of  these 

Fig.  570. 


collars  for  this  kind  of  work,  and  also  for  the  construction  of 
cap  crowns,  are  obvious. 

"  The  other  appliances  specially  devised  for  this  system  are,  a 
reducing-plate  or  contractor,  a  pair  of  collar  pliers,  and  a 
hammer. 

"The  contractor  (Fig.  570)  contains  holes  which  are  comple- 
mentary in  shape  to  the  mandrels.     The  mandrels  being  applied 


THE  MANDREL  SYSTEM. 
Fig.  571. 


291 


D 


« 


as  a) 


d8  as  a» 


I) 


a 


ae 


as 


t 


<i 


« 


(5 


o 


ft 


as 


o 


18 


W 


9 


o 

o 
o 
o 

O 
O 

O 


292  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

to  the  inner  circumferences  of  the  collars,  while  the  contractor 
must  admit  the  collars  themselves,  the  short  taper  of  the  holes 
in  the  contractor  necessarily  covers  a  somewhat  greater  range  of 
size  than  is  shown  in  the  mandrels.    With  this  appliance  collars 

Fig.  572. 


can  be  evenly  and  accurately  reduced  in  size  at  the  edges,  with- 
out burring  or  buckling.     The  illustration  is  actual  size. 

"  The  collar  pliers  (Fig.  572)  are  for  contouring  the  collars  to 
shape,  one  beak  being  made  convex  and  the  other  concave  to 


THE  MANDREL  SYSTEM. 


293 


Fig.  573. 


correspond.  With  this  appliance  the  slightest  changes  required 
in  the  contour  of  the  collars  are  easily  made.  About  a  half-inch 
from  the  extremity  of  the  concave  beak  a  small 
bar  of  flat  steel  is  attached  to  it  by  means  of  a 
screw.  The  free  end  of  the  bar  has  a  minute 
projection  upon  one  face,  the  other  being  rein- 
forced to  fit  into  the  concavity  of  the  beak.  In 
the  center  of  the  face  of  the  convex  beak  is  a 
depression,  into  which  the  projection  on  the 
steel  bar  strikes,  making  a  very  efficient  punch 
for  forming  guards  or  stops  to  prevent  the  col- 
lars from  being  forced  too  far  under  the  gum. 
The  depression  in  the  convex  beak  being 
slightly  larger  than  the  projection  or  punch, 
the  metal  is  not  cut  through,  but  merely  raised 
on  the  side  opposite  to  the  punch.  The  punch 
attachment  being  pivoted  can  be  swung  to  one 
side  when  not  in  use. 

"  Fig.  573  is  a  mallet  or  hammer,with  steel  face 
and  horn  peen.    The  handle  is  nine  inches  long. 

"  One  of  the  appliances  required  is  a  lead 
anvil,  which  being  only  a  piece  of  soft  lead  say 
two  by  three  inches,  and  an  inch  thick,  is  not 
illustrated.  The  female  die  of  an  ordinary  case 
will  answer  very  well. 

"  To  illustrate  the  uses  of  these  appliances, 
take  a  case  in  which  the  two  inferior  bicuspids 
of  the  left  side  are  missing,  and  the  crowns  of 
the  cuspid  and  first  molar  so  badly  decayed  that 
the  probabilities  are  that  they  will  soon  fall 
victims  to  the  forceps.  The  old-time  way  would 
have  been  to  extract  the  molar  and  cuspid, 
and  make  a  partial  plate.  Examination,  how- 
ever, shows  that  the  roots  of  these  two  teeth 
are  in  good  condition,  affording  an  excellent 
opportunity  for  the  construction  of  a  piece  of 
bridge-work. 

"With  a  corundum-point  or  rotary  file,  cut  off  the  remaining 


294  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

portions  of  the  crowns  level  with  the  gum-margins.  Prepare 
the  roots  in  any  of  the  well-known  ways,  thoroughly  cleansing 
the  apical  portions  and  filling  them  with  whatever  material  is 
desired,  being  careful  only  that  the  work  is  well  done.  For  the 
better  retention  of  the  filling-material  to  be  placed  in  the  pulp- 
chamber,  retaining-grooves  can  be  made  or  retaining-posts  in- 
serted. Take  a  piece  of  binding-wire  (ISTo.  26,  American  gauge), 
two  and  one-half  inches  long,  pass  it  around  the  neck  of  the  molar 
stump,  cross  the  free  ends,  and,  holding  the  wire  in  place  with  one 
finger,  twist  the  ends  with  a  pair  of  flat-nose  pliers  until  the  wire 
clasps  the  neck  closely  at  every  point  (Fig.  574).  Where  there 
are  any  irregularities  in  the  contour  of  the  tooth,  it  is  necessary 
to  press  the  wire  into  them  with  an  approximal  burnisher.  It  is 
obvious  that  the  ring  thus  formed  will  show  the  exact  size  and 
shape  of  the  neck  of  the  tooth.     Remove  the  ring  carefully,  lay 

Fig.  574.  Fig.  575. 


it  on  the  lead  anvil,  put  over  it  a  piece  of  fiat  metal,  and  with  a 
smart  blow  from  a  hammer  drive  the  wire  into  the  lead  (Fig. 
575).  Upon  removing  the  wire,  an  exact  impression  of  the  ring 
wTill  be  left  in  the  lead  anvil.  (This  part  of  the  work,  as  indeed 
all  others,  should  be  done  carefully  as  described.  The  wire  ring 
may  be  driven  into  the  lead  by  a  direct  blow  of  the  hammer 
face,  but  the  blow  might  not  strike  equally,  and  the  interposition 
of  the  flat  metal  held  level  insures  an  even  impression.  A  piece 
of  an  old  file  is  best,  as  the  file-cuts  keep  the  wire  from  slipping.) 
"Next,  cut  the  wire  ring  at  the  lap,  straighten  out  the  wire, 
and  select  a  suitable  collar  by  comparing  the  length  of  the  wire 
with  the  straight  lines  in  the  diagram  (Fig.  571),  which  show  the 
inside  diameters  of  the  various  sizes.  Should  none  of  these 
correspond  exactly,  take  preferably  the  next  size  smaller.  It  will 
be  remembered  that  the  collars  are  !No.  30  in  thickness,  while 


THE  MANDREL  SYSTEM. 


295 


Fig.  576. 


the  wire  with  which  the  conformation  is  secured  is  No.  26.  This 
difference  permits  the  collar  when  contoured  to  shape  to  enter 
the  lead  impression  readily,  a  decided  advantage  in  fitting. 
Having  selected  the  collar,  fit  it  to  mandrel  Xo.  5,  with  the  peen 
of  the  hammer,  holding  it  upon  the  lead  anvil,  and  using  a 
slight  pushing  force  to  help  in 
stretching  and  forming  it  (Fig. 
576).  Having  driven  the  collar  to 
form,  remove  it  from  the  mandrel 
and  try  in  the  lead  impression. 
If  it  does  not  fit  exactly,  return 
it  to  the  mandrel  and  stretch  it  a 
little,  when  it  will  usually  fit  per- 
fectly, as  the  mandrels  have  been 
designed  carefully  to  the  average 
shapes  which  obtain  in  the  great 
majority  of  tooth-necks.  In  the 
exceptional  cases  where  the  collar 
does  not  fit  it  can  be  readily  con- 
toured to  the  exact  shape  with  a 

pair  of  flat-nose  pliers.  Of  course,  if  it  fits  the  impression  in 
the  lead,  it  will  fit  the  neck  of  the  tooth,  always  provided  the 
measurement  and  the  impression  have  been  carefully  made. 

"  If  the  collar  or  band  has  been  accidentally  stretched   too 
much,  or  if  for  any  reason  when  brought  to  shape  it  is  too 
large,  its  root-end  can  easily  be  reduced  to  the  proper  size  by 
Fig.  577.  Fig.  578. 


the  use  of  the  contractor.  Place  the  edge  of  the  collar  which 
is  to  fit  the  root  in  the  proper  hole ;  hold  it  level  with  a  piece 
of  file  as  in  taking  the  lead  impression  of  the  ring,  and  tapping 
lightly  on  the  file  drive  the  collar  into  the  plate  (Fig.  577)  until 
the  proper  reduction  is  made.  The  collar  is  next  '  festooned' 
to  correspond  to  the  shape  of  the  maxillary  ridge.     Lay  it,  gum 


296 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


edge  up,  on  the  lead  anvil,  and  with  the  piece  of  flat  file  and 
the  hammer  drive  it  into  the  lead.  A  few  cuts  with  a  fine  half- 
round  file  across  the  approximal  diameter  will  conform  the 
edges  to  the  surface  of  the  ridge  (Fig.  578).  Then  place  the 
collar  in  position,  and  having  ascertained  just  how  far  it  should 
go  down  on  the  root,  remove  it,  and  with  the  small  spring  punch 
in  the  collar  pliers  form  projections  on  the  inside  of  the  band  at 
the  proper  points  to  serve  as  stops,  which,  resting  on  the  top  of 
the  root,  will  prevent  the  collar  from  being  forced  farther  down 
upon  it  than  is  desirable  (Fig.  570). 

"  A  collar  for  the  cuspid  is  then  fitted  in  the  same  manner, 
using  mandrel  No.  6  for  shaping,  after  which  the  case  is  ready 
for  the  building  of  the  bridge. 


Fig.  579. 


Fio.  580. 


"  Cement  with  oxyphosphate  both  collars  in  position.  Then 
take  an  impression  of  the  parts,  including  the  interiors  of  the 
excavated  pulp-chambers,  from  which  make  a  cast  in  the  usual 
way.  Bend  a  short  piece  of  half-round  gold  or  platinum  wire 
into  the  form  of  a  horse-shoe,  the  two  extremities  of  which 
shall  fit  into  the  roots  of  the  molar.  Then  take  a  longer  piece 
of  the  same  wire,  somewhat  more  than  enough  to  extend  from 
the  toe  of  the  horse-shoe  when  in  position  to  the  cuspid  root  ; 
bend  one  end  of  it  at  a  right  angle,  or  nearly  so,  to  fit  the  root 
of  the  cuspid,  and  (cutting  off  any  excess  of  length)  solder  the 
other  end  to  the  toe  of  the  horse-shoe.  The  bar  extending 
between  the  two  roots  is  the  truss  of  the  bridge.  Next,  place 
the  appliance  on  the  cast  (Fig.  580),  holding  it  in  position  with 


THE  MANDREL  SYSTEM.  097 

wax,  and  select  the  teeth  to  take  the  place  of  the  missing 
bicuspids  and  molar.  The  best  form  for  this  purpose  is  a  tooth 
having  holes  extending  through  it  vertically  from  the  neck  to 
the  grinding-surface  similar  to  the  well-known  Bonwill  crown. 

"  The  crowns  used  should  be  large  enough  to  fill  the  space 
rather  tightly,  even  if  their  sides  have  to  be  flattened  slightly  to 
let  them  in.  If  the  teeth  do  not  fill  the  space  tightly,  a  small 
portion  of  plastic  filling-material  crowded  between  them,  as 
mortar  between  the  granite  blocks  in  the  arch  of  a  railway 
bridge,  will  greatly  increase  the  strength  of  the  work. 

"  After  the  teeth  are  ground  to  fit  and  the  proper  length  for 
occlusion  is  ascertained,  the  truss  is  covered  with  a  thin  film  of 
wax,  upon  which  the  crowns  are  again  pressed  to  their  positions. 
Upon  the  removal  of  the  crowns  the  impression  of  the  holes 
running  through  them  will  be  found  in  the  wax.  At  these 
points  drill  holes  through  the  bar  with  a  small  twist-drill  run  by 
the  engine,  and  into  these  fit  and  solder  the  pins  for  the  support 
of  the  crowns. 

"  The  bridge  is  now  ready  to  be  attached  permanently.  Set 
the  crowns  in  position  upon  their  supporting  pins  to  secure  the 
proper  alignment.  (If  the  operation  were  upon  the  upper  jaw 
they  would  have  to  be  held  with  wax.)  Put  into  the  canals  of 
the  supporting  roots  (the  cuspid  and  first  molar)  a  sufficient 
quantity  of  some  quick-setting  plastic,  as  oxyphosphate,  to  about 
half  fill  the  pulp-chamber,  but  not  enough  to  prevent  the  sup- 
ports of  the  truss  from  being  forced  home.  Force  the  bridge 
supports  to  place,  and  after  allowing  the  filling-material  to  become 
set  remove  the  crowns.  Fill  the  remainder  of  the  pulp-chamber 
and  the  whole  of  the  collar  with  gold  or  with  amalgam,  gutta- 
percha, oxyphosphate,  or  any  suitable  plastic  (Fig.  581).  Set 
the  crowns  permanently,  the  molar  and  cuspid  first,  as  this 
affords  greater  facility  for  the  trimming  off  of  any  excess  of  the 
filling-material  used  in  the  attachment.  For  attachment  of  the 
crowns,  gutta-percha  is  probably  the  best  material,  as  crowns 
set  with  it  are  readily  removed  for  the  correction  of  any  in- 
accuracies of  occlusion  or  alignment,  by  grasping  them  between 
the  beaks,  previously  warmed,  of  a  pair  of  universal  lower 
molar  forceps.     The  heat  warms  the  gutta-perclm  and  releases 


298 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


the  tooth,  which  can  then  be  reset  properly.  In  attaching 
crowns  with  gutta-percha  the  holes  in  the  crowns  are  first  filled 
with  the  material,  after  which  the  crown  is  warmed  and  forced 
to  place.     Any  of  the  other  plastics  ordinarily  used  in  setting 


Fig.  581. 


Bonwill    crowns    can    be    employed,    at   the    discretion   of  the 
operator.     Fig.  582  shows  the  case  completed. 

"  In  securing  the  occlusion  of  a  piece  of  bridge- work  it  is  well 
to  make  the  artificial  teeth  a  little  short,  so  that  the  natural  teeth 
on  both  sides  will  meet  the  first  shock  of  mastication.  Nature 
will  correct  the  occlusion  in  time  by  slightly  elongating  the 
roots  supporting  the  bridge.  If  the  artificial  crowns  are  per- 
mitted to  strike  the  natural  teeth  from  the  first,  the  undue  strain 

Fig.  582. 





upon  the  two  supporting  roots  may  cause  soreness  and  perhaps 
more  serious  consequences. 

"  When  a  sound  tooth  is  to  be  used  as  one  of  the  supports  of 
the  bridge,  a  modification  of  the  method  just  described  is 
necessary.  Take  a  case  where  it  is  desired  to  bridge  the  space 
caused   by  the   loss  of   the  right  inferior   bicuspids  and   first 


THE  MANDREL  SYSTEM.  299 

molar.  The  crown  of  the  right  cuspid  is  nearly  gone,  but  the 
root  is  sound  and  capable  of  supporting  one  end  of  the  bridge. 
The  other  end  will  be  attached  to  the  second  molar,  which  is 
a.  sound  tooth.  Prepare  and  band  the  cuspid  root  as  before; 
dress  off  the  second  molar  crown  until  it  is  slightly  smaller  than 
the  neck,  and  shorter  at  the  occluding  surface,  so  as  to  permit 
a  cap  to  be  telescoped  over  it,  and  take  the  measure  of  the 
crown  with  the  binding-wire.  Select  a  suitable  seamless  collar 
of  sufficient  width  to  extend  from  the  neck  to  a  little  beyond  the 
grinding-surface,  and  drive  it  up  on  the  proper  mandrel  to  get 
the  general  shape,  but  not  the  full  size  required  to  fit  the  tooth, 
leaving  it  so  that  the  edge  having  the  larger  circumference  will 
just  pass  over  the  end  of  the  crown;  place  the  collar  on  the 
tooth,  and  with  a  block  of  wood  and  the  mallet  tap  it  to  place 

Fig.  583. 


____. — - — . -  - 


just  beyond  the  free  margin  of  the  gum.  This  method  will 
make  a  close  fit,  as  the  collar  will  readily  stretch  all  that  is 
necessary.  With  a  sharp-pointed  instrument  mark  the  length 
of  the  crown  and  line  of  the  gum-margin,  remove  the  collar, 
and  cut  it  to  the  proper  form  as  indicated.  Then  in  a  piece  of 
gold  plate  of  the  thickness  used  for  caps  form  four  little  depres- 
sions of  the  general  character  of  an  impression  of  the  molar 
cusps.  An  easy  way  to  do  this  is  to  lay  the  plate  on  the  lead 
anvil;  then  with  the  ball  on  the  end  of  an  ordinary  socket- 
handle  and  the  hammer  the  depressions  are  made  in  a  moment. 
Clamp  the  collar  on  the  plate,  borax  it,  charge  with  solder,  and 
heat  till  the  solder  Hows.  Cut  off  the  surplus  plate,  and  a  per- 
fect  cap  for  the  molar  is  made.  Place  it  on  the  tooth  and  take 
an  impression,  and  thereafter  proceed  as  before  directed  to  make 


300  ARTIFICIAL    CROWN-  AXD  BRIDGE-WORK. 

the  truss  of  the  bridge  and  mount  the  teeth,  except  that  in  this 
case  the  posterior  end  of  the  truss  is  to  be  soldered  to  the  molar 
cap.  For  the  final  attachment  place  a  little  oxyphosphate  in  the 
cap  to  secure  it  firmly  (Fig.  583),  first  cutting  a  slot  in  the  crown 
end  of  the  cap  for  the  escape  of  the  excess  of  material.  Pressure 
upon  the  filling-material  hastens  its  hardening."     .     . 

DETACHABLE    BRIDGE-WORK. 

"  A  method  of  constructing  a  detachable  bridge  applicable 
to  cases  where  one  or  both  of  the  supports  or  piers  are  sound 
teeth  is  as  follows :  In  the  case  adduced  for  illustration  the 
right  inferior  cuspid  crown  was  decayed,  and  both  of  the  bi- 
cuspids and  the  first  molar  were  absent.  The  supports  for  the 
bridge  were  the  sound  second  molar  and  the  cuspid  root.  After 
the  cuspid  root  was  prepared  and  banded,  the  crown  of  the 

Fig.  584. 


molar  was  reduced  very  slightly, — not  sufficient  to  destroy  the 
enamel,  but  just  enough  to  permit  a  collar  properly  fitted  to  pass 
over  it.  A  collar  somewhat  wider  than  the  length  of  the  crown 
from  grinding-surface  to  neck  was  fitted  and  cut  to  the  proper 
width.  Two  lugs  were  then  soldered  upon  the  anterior  and 
posterior  sides  and  bent  to  fit  into  the  approximal  fissures,  which 
were  slightly  cut  out  to  admit  them.  An  impression  was  taken, 
the  collar  coming  away  in  the  plaster,  and  a  cast  was  made  with 
the  collar  in  position.  A  coned  tube  was  then  made  for  the 
root  of  the  cuspid  and  a  coned  pin  fitted  into  it.  A  truss  of 
half-round  wire  was  made,  to  which  the  coned  pin  and  the  molar 
collar  were  soldered  (Fig.  584).  A  half-clasp  to  grasp  the  lateral 
was  next  soldered  to  the  end  of  the  truss  to  be  supported  by  the 


DE  TA  CHA  BLE  BR  ID  G  E-  WORK. 


301 


cuspid.  The  object  of  this  clasp  was  to  guard  against  the  teeth 
being  thrown  out  of  proper  alignment  by  the  force  of  mastica- 
tion. Bonwill  crowns  were  then  vulcanized  to  the  truss,  after 
their  supporting  pins  had  been  fitted  and  soldered  to  it.  (Counter- 
sunk crowns  can  be  used  as  well  in  the  same  way.  Plain  plate 
teeth  may  also  be  used  in  this  style  of  work,  in  which  event  they 
are  to  be  soldered  to  the  truss.)  The  bridge  was  then  ready  to 
be  set,  which  was  accomplished  in  the  following  manner :  The 
cuspid  root  was  nearly  filled  with  oxyphosphate,  and  the  coned 
tube  was  placed  upon  the  pin.  The  band  was  put  on  the  molar, 
and  the  coned  pin  with  the  tube  upon  it  was  forced  into  the 
plastic  in  the  cuspid.  As  soon  as  this  became  set,  the  tube  was 
held  permanently,  while  the  bridge  itself  could  be  removed 
whenever  desired  (Fig.  585). 

Fig.  585. 


"  This  method  of  fixing  the  tube  allows  considerable  range  in 
its  adjustment.  In  soldering  the  coned  pin  to  the  truss,  care 
should  be  taken  to  set  it  at  an  angle  exactly  parallel  to  the  axis 
of  the  molar ;  otherwise  there  will  be  difficulty  in  removing  the 
bridge. 

"  A  second  style  of  detachable  bridge-work  to  be  described 
involves  the  use  of  cusp  crowns  (Fig.  586)  for  supporting  posts 
or  piers.  Suppose  a  case  where  a  bridge  is  required  to  extend 
from  the  right  inferior  cuspid  to  the  right  inferior  second  molar, 
with  only  the  roots  of  the  two  teeth  named  as  supports.  Prepare 
the  roots  and  pulp-chambers.  Set  screw-posts  into  the  dentine 
for  anchorage  or  as  retaining-pins,  and  fit  the  collars,  using  sizes 
wide  enough  to  form  the  walls  of  the  crowns.  Fill  the  pulp- 
chamber  and  cement  on  the  collars,  filling  about  two-thirds  of  the 


302  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

depth  of  the  collars  with  a  plastic  filling-material,  packing  it  well 
around  the  retaining-posts.  Select  suitable  cusp  crowns  for  the 
molar  and  cuspid,  and  place  them  in  the  ends  of  the  bands  to 
ascertain  the  occlusion.  If  too  long,  shorten  the  cusps  or  reduce 
the  bands  with  engine  corundums  or  rotary  files,  and  when  the 
correct  articulation  is  found  form  a  small  square  shoulder  in  the 
lingual  edge  of  the  cuspid  and  in  the  posterior  grinding-surface 
of  the  molar.  Fill  the  remaining  portion  of  the  collars  with 
plastic  mixed  somewhat  thinner  than  the  first  lot,  and  set  the 
cusp  crowns  in  position.  If  there  are  antagonizing  teeth,  the 
mere  closing  of  the  patient's  jaws  will  force  the  crowns  to  place. 
If  there  are  no  antagonizing  teeth  the  crowns  can  be  readily 
tapped  to  place  with  the  mallet,  using  a  piece  of  wood  as  a 
driver.  Allowr  the  filling-material  to  set  firmly,  trimming  off 
any  excess  which  may  exude  around  the  collars. 

Fig.  586. 


"  Bridge  supports  or  piers  constructed  on  this  plan  are  strong 
and  durable,  and  likely  to  withstand  any  strain.  Take  an 
impression,  and  proceed  to  fit  seamless  collars  to  telescope  over 
those  already  set  upon  the  cuspid  and  second  molar  roots.  It 
will  be  remembered  that  these  collars  are  so  made  that  each  size 
telescopes  into  the  next  higher  series.  If  the  proper  sizes  are 
selected  for  the  outside  or  female  bands,  the  work  of  fitting  is 
readily  and  quickly  accomplished,  forming  tubes  which  slide 
easily  over  the  supporting  piers,  and  at  the  same  time  fit  closely. 
It  is  only  necessary  to  take  care  in  shaping  the  tubes  not  to  drive 
them  too  far  up  on  the  mandrels  and  thus  stretch  them  so  as  to 
destroy  the  fit.  To  the  outer  end  of  each  of  the  tubes  solder  a 
small  piece  of  gold  plate,  forming  partial  caps  so  placed  as  to 
rest  when  in  position  upon  the  shoulders  previously  cut  in  the 
cusp  crowns.  Adjust  a  truss  bar  of  half-round  gold  wire,  to  the 
ends  of  which  solder  the  tubes.     The  truss  is  now  readv  for  the 


DETACHABLE  BRIDGE-  WORK. 


303 


teeth,  which  may  be  of  any  of  the  forms  used  for  this  purpose, 
and  they  may  be  attached  to  the  bar  in  any  way  desired.  One 
of  the  strongest  attachments  is  vulcanite.  Fig.  587  shows  the 
construction  and  the  finished  case. 


Fig.  587. 


"  An  easy  modification  of  the  plan  just  described  is  readily 
adapted  to  cases  where  only  a  small  space  is  to  be  filled  and  one 
end  of  the  bridge  is  to  be  supported  by  a  sound  tooth.  Thus, 
suppose  it  is  desired  to  bridge  a  space  formerly  occupied  by  the 
two  inferior  left  bicuspids,  the  crown  of  the  first  molar  being  a 
mere  shell.     The  operation  would  be  essentially  the  same  as  in 


Fig.  588. 


Fig.  589. 


the  previous  case,  except  that  the  sound  cuspid  would  be  utilized 
for  one  of  the  piers  as  follows  :  Fit  a  seamless  collar,  cut  out  a 
portion  of  it  so  that  it  will  embrace  only  about  two-thirds  of  the 
cuspid  crown,  and  solder  a  partial  cap  or  cover  to  it,  as  illustrated 


304  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

in  Fig.  588.  Or,  if  deemed  preferable,  the  cuspid  may  be  sepa- 
rated from  the  lateral  incisor  with  the  corundum-disk,  and  the 
collar  allowed  to  embrace  the  whole  crown. 

"  A  crown  broken  from  a  bridge  constructed  by  any  of  the 
methods  above  described  can  be  easily  substituted,  and  the  piece 
when  repaired  will  be  as  strong  and  serviceable  as  it  was 
originally. 

Fig.  590. 


"  It  has  not  been  deemed  necessary  to  detail  the  construction 
of  a  single  crown  separately,  as  all  the  steps  are  included  in  the 
building  of  bridges,  which  have  been  described  minutely.  Por- 
celain cusps  of  the  general  form  illustrated  in  Fig.  589  have  been 
designed  specially  for  these  cases.  In  mounting  them  the  gold 
band  is  cut  away  on  the  buccal  side  as  shown  in  Fig.  590,  to 
permit  the  porcelain  to  show." 


CHAPTER    XVIII. 

PORCELAIN  BRIDGE-WORE. 

For  an  ideal  piece  of  bridge-work  that  will  dispense  with  the 
objectionable  features  of  a  permanently  attached  bridge  and 
refute  the  most  forcible  arguments  against  the  system,  porcelain 
is  the  most  suitable  material  known. 

DR.    BROWN'S    METHOD. 

Dr.  E.  Parmly  Brown  has  invented  and  introduced  a  method 
of  porcelain  and  iridio-platinum  bridge-work.  The  advantages 
claimed  for  it  as  a  method  of  bridge-work  are  as  follows: 

It  is  formed  entirely  of  porcelain  and  platinum,  and  presents 
a  perfect  continuity  of  porcelain  surface. 

It  is  unaffected  by  any  chemical  action  or  condition  in  the 
mouth. 

As  the  base  of  each  tooth  presses  tightly  onto  the  membranes 
of  the  gum,  which  closes  or  hugs  closely  around  it,  no  so-called 
self-cleansing  spaces  are  required. 

A  benign  form  of  contour  is  presented  on  its  palatal  surface. 

And  lastly,  it  has  the  merit  of  simplicity  of  construction  in 
comparison  with  the  other  methods  in  practice. 

Construction. — The  bridge  is  formed  by  spanning  intervening 
spaces  between  certain  natural  teeth  or  roots  with  artificial 
porcelain  substitutes  baked  onto  an  iridio-platinum  bar,  or  bar 
and  plate;  either  or  both  ends  of  the  bar  being  anchored  in  a 
crown,  or  in  a  filling  inserted  in  the  approximal  portion  of  the 
adjoining  tooth.  The  roots  to  be  crowned  and  used  as  founda- 
tions for  the  bridge  are  prepared  as  for  single  crowns.  If  the 
end  of  the  bar  is  to  be  fixed  in  a  natural  tooth,  the  cavity  that 
is  to  receive  and  anchor  it  is  opened  up  to  properly  admit  it,  as 
described  on  pages  181  and  184.     A  square  bar  of  iridio-platinum 

21  805 


306 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  591. 


wire,  from  Xo.  13  to  Ko.  15,  U.  S.  standard  gauge  in  thickness, 
is  fitted  either  to  the  cavities  of  the  teeth  in  which  it  is  to  be 
anchored,  or  bent  and  fitted  in  any  devitalized  tooth  or  root 
which  is  to  act  as  an  abutment.  The  end  of  the  wire  that  forms 
the  post  is  pointed  and  introduced  well  up  the  root-canal,  and 
the  end  forming  the  bar  is  slightly  flattened  or  squared.  Any 
intervening  root-posts  are  fitted  and  riveted  to  the  bar  as  it 
passes  above  them.  Caps  of  platinum  are  next  formed  for  the 
ends  of  the  roots  (Fig.  591).     This  is  done  by  swaging,  or  by 

adapting  thin  platinum  plate  to  the  ends 
of  the  roots  in  the  mouth,  then  slitting 
the  edges  and  bending  them  over  the 
sides.  The  electric  mallet  can  be  used 
to  aid  the  operation.  The  caps  are  per- 
forated for  the  posts,  and  soldered  to 
them  in  correct  position  with  pure  gold. 
When  the  base  of  the  bridge  resting 
on  the  gums  is  formed  entirely  of  por- 
celain, ordinary  plate  teeth1  are  to  be  used  and  fastened  to  the 
bar  by  slightly  flattening  the  bar  and  riveting  the  pins  firmly, 
or  when  straight-pin  teeth  are  used  by  bending  the  pins  over 
the  bar  (Fig.  592);  bicuspid  and  molar  teeth  with  straight  pins, 
by  grinding  a  slot  with  a  disk  between  the  pins 
and  bending  them  over  the  bar,  which  is  slightly 
barbed  and  set  in  the  slot. 

The  proper  position  of  every  tooth  having  been 
determined  by  adjustment  in  the  mouth,  or  to  the 
articulating  model,  the  rivets  and  bar  to  each 
one  are  carefully  filled  around  and  the  cervico- 
palatal  portion  rounded  off  with  porcelain  body  so  as  to  present 
a  smooth  surface  to  the  tongue.  The  shape  of  the  end  of  the 
root  is  given  to  the  crown  by  placing  the  porcelain  body,  to 
which  a  small  quantity  of  starch  has  been  added,  around  the 
post  as  it  is  fixed  in  position  on  the  model ;  the  plaster  having 
been  previously  varnished  with  collodion  to  prevent  cohesion. 

1  Dr.  Brown  uses  American  teeth  entirely  for  this  work,  as  he  has  found  them 
the  most  suitable,  being  the  only  kind  that  will  retain  their  color  in  the  intense 
heat  to  which  they  are  subjected. 


Fig.  502. 


PORCELAIN  BRIDGE-WORK. 


307 


The  spaces  between  the  teeth  on  the  line  of  the  bar  are  to  be 
substantially  joined  with  the  porcelain  body ;  free  spaces  between 
the  teeth  at  the  cervical  portion  are  to  be  preserved  as  much  as 
possible  without  interfering  with  strength  or  producing  places 
that  will  be  uncleanly. 

The  bridge  is  then  placed  on  a  slide  in  the  muffle  of  a  con- 
tinuous-gum furnace.  It  is  sustained  in  position  by  inserting 
the  pins  in  holes  drilled  in  the  slide  (Fig.  593),  or  by  suspending 
it  with  platinum  wire  between  two  platinum  posts  inserted  in 
the  slab.  The  bridge  is  then  baked  the  same  as  continuous-gum 
work.  It  is  next  fitted  to  the  mouth.  If  any  alterations  are 
required  they  should  be  made;  or  if  any  imperfections  in  the 
body  occur,  the  places  should  be  tilled  in  and  the  bridge  again 
baked.     It  is  then  ready  for  insertion. 

Fig.  593. 


A  preferable  method  of  constructing  porcelain  bridges  is  to 
form  the  base  of  the  bridge  on  an  iridio-platinum  plate.  A  space 
the  size  of  the  base  of  the  teeth  to  be  replaced  is  first  marked 
on  a  plaster  model  of  the  case.  The  plaster  is  removed  at  the 
labial  and  palatal  sides,  gradually  deepening  to  the  edge  of  the 
line  of  the  space.  This  is  to  cause  the  margin  of  the  plate  to 
press  in  the  gums.  A  metallic  cast  is  then  made,  and  an  iridio- 
platinum  plate  Xos.  30  to  31  gauge  struck  up. 

The  teeth  and  bar  are  placed  in  position  on  the  plate  (in  this 
case  continuous-gum  teeth  are  used);  the  pins  of  the  teeth  are 
bent  over  the  bar  on  the  plate  and  soldered  to  it  with  pure  gold. 

When  one  end  of  the  bridge  is  supported  by  an  all-gold  crown 
on  a  tooth  with  a  living  pulp,  the  end  of  the  bar  is  passed  into 


308 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


the  grinding-surface,  or  flattened  and  bent  against  the  side  of 
the  gold  crown  and  soldered  to  it.  This  is  done  by  investing  in 
asbestos  and  plaster  and  carefully  heating  up  the  porcelain  before 
using  the  blow-pipe. 

Insertion. — When  the  bridge  is  supported  by  crowns  alone,  the 
posts  are  barbed  and  the  bridge  is  then  cemented  on,  the  same  as 
any  other.  If  one  end  is  supported  by  a  porcelain  crown  and 
the  other  by  a  bar,  the  filling  on  the  bar  end  is  inserted  up  to  the 
position  the  bar  is  to  occupy  before  fastening  the  post  of  the  crown 
end,  which  is  then  cemented  and  the  filling  of  the  bar  end  com- 
pleted.    (See  "  Bar  Bridges.") 


Fig.  595. 


Fig.  596. 


Fig.  597. 


In  Fig.  594,  No.  1  is  a  third  molar,  pulp  alive,  with  large 
filling;  No.  2  is  a  porcelain  bridge;  No.  3  is  a  first  molar,  pulp 
dead,  with  a  metal  bar  entering  the  pulp-chamber. 

In  Fig.  595,  No.  1  is  a  second  molar,  pulp  alive,  with  a  crown 
filling  of  gold  or  amalgam  retaining  the  bar;  No.  2  is  a  porce- 
lain bridge ;  No.  3  is  a  gold  crown  with  bar  passing  through 
one  side  of  the  crown  into  the  root. 

Fig.  596  is  a  view  of  a  central  incisor  bridged  onto  two  teeth 
whose  pulps  have  been  lost. 

Fig.  597  is  a  view  of  an  extension  bridge  consisting  of  a  right 
central  and  left  lateral,  supported  by  a  left  central  tooth  or  crown 
as  the  case  may  be.  The  bar  can  be  anchored  in  a  filling  in  the 
natural  crown  or  attached  to  the  artificial  one.     Nos.  1  and  3 


PORCELAIN  BRIDGE-  WORK. 


309 


are  teeth  on  a  porcelain  bridge ;  Xo.  2  the  natural  tooth  or  arti- 
ficial crown  on  which  the  bridge  is  saddled. 

Figs.  598,  599,  and  600  represent  a  bridge  of  eleven  teeth 
inserted  by  Dr.  Brown  on  two  cuspid  roots,  a  pulpless  molar 


Fig.  598. 


on  the  left  side  which  was  capped  with  a  gold  crown,  through 
the  side  of  which  the  bar  was  passed  and  anchored  in  the  root, 


Fig.  599. 


Fig.  600. 


and  a  molar  on  the  right  side  into  which  the  other  end  of  the 
bar  was  anchored  in  a  gold  filling. 

Fig.  601  represents  a  bicuspid  bar-bridge  anchored  in  the  molar 
and  first  bicuspid.     The  side  cut  shows  the  construction.     This 


310 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


operation  was  performed  by  Dr.  Brown  for  Dr.  Wm.  Crenshaw, 
at  the-  anniversary  clinic  of  the  First  District  Dental  Society  of 
the  State  of  New  York,  in  January,  1887. 


Fig.  601. 


Fig.  602 1  represents  an  extension  bridge  in  which  the  support 
consists  of  a  crown  and  bar  combined. 

Fig.  603  represents  an  extension  bar-bridge.  The  filling  in 
the  second  bicuspid,  which  extended  from  the  mesial  to  the 
distal  side,  had  been  inserted  some  time  previously.  Enough  of 
the  gold  was  removed  from  the  mesial  section  of  the  filling  to 


Fig.  602. 


Fig.  603. 


admit  the  bar,  which  was  then  securely  anchored  and  the  filling 
restored  to  its  original  form.  The  operation  was  performed  by 
Dr.  Brown  for  Dr.  F.  P.  Hamlet.  The  antagonizing  teeth  in  the 
act  of  occlusion  favor  the  artificial  tooth  forming  the  bridge. 


xCase  of  Dr.  F.  P.  Hamlet. 


PORCELAIN  BRIDGE-WORK. 


311 


In  porcelain  bridge-work,  should  a  case  require  it,  artificial 
gum  in  a  moderate  amount  can  be  formed  above  the  teeth  of 
the  bridge,  to  restore  the  contour  of  the  parts.     Figs.  604  and 

Fig.  604. 


Fig.  605. 


Fig.  606. 


^05  illustrate  a  case  of  this  character.  A,  Fig.  606,  shows  the 
labial  and  B  the  lingual  aspect  of  the  incisor  bridge  before 
insertion. 


312 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  607  represents  a  case  restored  by  Dr.  Brown's  method 
by  Dr.  M.  L.  Rhein.  To  remedy  the  abnormal  character  of  the 
occlusion,  the  lower  anterior  teeth  and  the  right  upper  cuspid 


Fig.  607. 


Fig.  608. 


Fig.  609. 


were  trimmed  to  the  dotted  line  seen  in  the  figure.  To  replace 
the  missing  teeth  porcelain  bridge-work  was  then  constructed. 
The  lateral  and  central  roots,  and  the  right  cuspid  and  the  molary 


Fig.  610. 


constituted  the  abutments.     On  the  central  and  lateral  roots 
were  mounted  caps  with  collars.     A  platinum  crown  was  then 


PORCELAIN  BRIDGE-WORK. 


313 


made  for  the  cuspid  (Fig.  608),  and  to  this  crown  was  attached 
the  bar,  which  was  extended  to  its  anchorages  in  the  molar 
crown  and  the  lateral  and  central  roots,  the  caps  on  the  ends  of 
which  the  posts  pierced.  Owing  to  the  large  quantity  of  porce- 
lain body  to  be  used  in  forming  the  artificial  gum,  a  strip  of 
platinum  plate  was  extended  above  the  bar  to  stiffen  its  pro- 
jecting ends  and  prevent  warpage  in  baking.  The  artificial 
teeth  were  then  articulated  to  meet  the  incisive  edges  of  the  in- 
ferior natural  teeth,  and  thus  in  a  measure  overcome  the  deformity 


Fig.  611. 


caused  by  the  abnormal  occlusion.  In  doing  this  the  labial 
aspect  of  the  cuspid  was  covered  by  the  artificial  teeth.  Porce- 
lain gum  was  then  formed  above  the  teeth  in  sufficient  quantity 
to  restore  the  contour  of  the  parts.  It  was  brought  to  a  feather 
edge  and  pressed  hard  against  all  the  tissues  to  insure  a  hygienic 
condition.  Fig.  609  shows  the  finished  bridge.  In  Fig.  610 
the  bridge  is  seen  in  position.  The  artistic  result  and  improved 
appearance  effected  are  at  once  apparent.  The  mechanical  con- 
struction of  the  piece  was  intrusted  to  Dr.  C.  L.  Andrews. 


314 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Figs.  611  and  (312  represent  an  upper  and  lower  case  of  por- 
celain bridge-work,  inserted  by  Dr.  Vm,  Crenshaw,  in  which 
several  roots  and  teeth  were  used  to  form  the  necessary  abut- 
ments. The  upper  section  anteriorly  receives  the  combined 
support  of  several  roots  as  illustrated  in  Fig.  611.  The  bar  on 
the  left  side  is  made  flat  and  hooked  on  the  end,  affording  a 
secure  means  of  anchorage.  A  gold  crown  forms  the  support  on 
the  right.  The  lower  section  is  firmly  supported  on  the  right 
side  by  passing  the  bar  through  the  cuspid  and  inserting  the  end 
in  the  pulpless  bicuspid  as  illustrated  in  Fig.  612.  The  pulpless 
bicuspid  on  the  left  constitutes  the  other  abutment. 

Fig.  612. 


Dr.  Brown's  system  and  method  of  bridge-work  compares 
with  other  forms  of  bridge- work  as  continuous-2;um  work  com- 
pares  with  other  forms  of  plate-work.  In  cleanliness,  through 
the  unalterable  character  and  continuity  of  its  surface  and  the 
incorruptibility  of  the  material,  it  has  advantages  as  a  denture. 
The  ultimate  value  of  this  method,  however,  as  a  means  of 
replacing  lost  members  of  the  dental  arch,  depends,  like  others, 
on  its  proper,  correct,  and  skillful  application  to  cases  where  the 
occlusion  and  other  conditions  are  suitable  for  it. 


CHAPTER   XIX. 

■CROWN-  and  bridge-work  combined  with  operative 

DENTISTRY  IN  DENTAL  PROSTHESIS. 

The  combination  of  operations  on  the  natural  teeth  with  crown- 
and  bridge-work  affords  extraordinary  advantages  in  dental 
prosthesis.  The  results  which  can  be  accomplished  commend 
the  plan  strongly  to  the  experienced  practitioner.  A  few  cases 
are  adduced  in  illustration. 

Fig.  613. 


A  case  which  was  interesting,  owing  to  the  conditions  pre- 
sented and  the  various  operations  connected  with  it,  is  illustrated 
in  Fig.  613.  Fig.  614  shows  the  methods  and  operations  prac- 
ticed, and  Fig.  615  the  case  completed. 

The  upper  front  teeth  show  the  effects  of  abrasion  on  the  in- 
cisive edges  and  occluding  surfaces.  The  bicuspids  and  molars 
were  affected  with  pyorrhea  alveolaris.  The  four  incisors  and 
the  left  cuspid  were  pulpless,  and  alveolar  abscess  existed  at  the 
roots  of  three  of  the  incisors.  The  abscesses  and  root-canals 
were  properly  treated.  Gold  collar  crowns  with  porcelain  fronts, 
having  flat  incisive  edges  which  entirely  protected  the  porcelain 

315 


316 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


fronts  and  slightly  opened  the  bite,  were  made  for  the  incisors  and 
left  cuspid  (Fig.  614).  The  bicuspids  and  molars  were  placed 
in  as  hygienic  a  condition  as  possible  by  treatment.     On  the 


Fig.  614. 


left  side  a  dummy  bicuspid  with  a  bar  which  fitted  in  a  slot  formed 
to  receive  it  in  the  occluding  surface  of  the  second  bicuspid 


Fig.  615. 


was  attached  to  the  cuspid  crown.     When  the  cuspid  crown 
with  the  dummy  bicuspid  was  cemented  in  position,  the  bar  was 


OPERATIVE  DENTISTRY  WITH  CROWN-  AND  BRIDQE-WORK.    317 

anchored  in  the  slot  in  the  second  bicuspid  with  amalgam.  The 
cuspid  root  being  very  firm,  stability  was  thus  imparted  to  the 
natural  bicuspid,  which  was  quite  loose  because  of  absorption  of 
its  socket.  On  the  right  side  the  second  bicuspid  was  entirely 
capped  with  a  gold  seamless  crown.  On  the  anterior  side  of  this 
gold  crown  an  artificial  tooth  was  attached  as  a  dummy  first 
bicuspid,  with  a  bar  extending  from  its  anterior  side  and  fitted 
into  a  slot  formed  in  the  incisive  surface  of  the  natural  cuspid 
crown.  From  the  posterior  side  of  the  second  bicuspid  gold 
crown  a  bar  wras  extended  backward  into  the  side  of  the  molar. 
When  the  gold  crown  was  cemented  in  position  on  the  second 
bicuspid,  the  anterior  bar  was  firmly  anchored  in  the  cuspid  with 
a  gold  filling,  which  also  lengthened  the  incisive  edge,  and  the 
posterior  bar  was  fixed  in  the  molar  with  amalgam.  The  reasons 
for  this  form  of  construction  are  :  The  second  bicuspid  was  very 
loose  in  its  socket,  and  the  molar,  though  comparatively  more 
stable,  was  also  similarly  affected.  The  attachment  of  the  bar 
in  the  cuspid  supported  the  dummy  bicuspid  and  steadied  the 
second  bicuspid,  and  the  extension  of  the  posterior  bar  into  the 
molar  likewise  afforded  additional  support  to  the  bicuspid.  The 
pulp  of  the  molar  being  exposed,  was  devitalized,  removed,  and 
the  canal  properly  filled.     Fig.  615  shows  the  completed  case.1 

The  lower  teeth,  in  comparison  with  the  upper,  were  but 
slightly  abraded.  The  cuspids  and  one  of  the  incisors  were 
tipped  with  gold.  The  molars  on  the  left  side  were  absent,  so 
that  bridge-work  on  the  upper  jaw  on  that  side  between  the 
bicuspid  and  molar  would  have  been  to  no  purpose. 

In  the  case  presented  in  Fig.  616  the  operative  procedures  were 
confined  to  the  upper  jaw,  the  lower  teeth  of  the  patient  being 
in  good  condition.  The  bicuspids  and  the  first  and  second 
molars  of  both  sides  of  the  upper  jaw  had  been  lost  many  years 
before,  and  the  incisors  and  cuspids  showed  the  effects  of  extensive 

1  Recently,  during  the  presence  of  the  patient  in  my  office,  these  operations 
were  examined  by  members  of  the  profession,  and  pronounced  apparently  in  as 
perfect  condition  as  when  completed  four  years  ago.  The  treatment  of  the  teeth 
affected  with  pyorrhea  and  the  support  imparted  to  them  by  their  attachment  to 
the  other  firm  teeth  and  to  each  other  had  apparently  checked  the  disease,  and 
the  affected  teeth  appeared  to  be  more  secure  in  their  sockets  than  before  the 
insertion  of  the  bridsre-work  and  crowns. 


318 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


abrasion.  The  occlusion  was  sustained  and  the  principal  part 
of  mastication  performed  by  the  incisors,  as  the  third  molars 
had  been  forced  backward  and  antagonized  only  very  slightly  on 
one  side. 

The  patient,  a  gentleman,  had  had  a  plate  inserted,  to  the  pres- 
ence of  which  he  had  vainly  endeavored  to  accustom  his  mouth. 
The  abrasion  of  the  incisors  and  cuspids  was  of  the  rapidly  pro- 


Fig.  61 


gressive  character.  These  teeth  were  contoured  with  gold  foil  to* 
the  form  shown  in  Fig.  618,  and  a  wire  post  was  inserted  in  the 
right  lateral,  which  was  pulpless.  At  the  occluding  section  of  each 
filling,  the  layer  of  gold,  after  being  packed  with  the  plugger,. 
was  additionally  condensed  and  hardened  with  a  Herbst  agate- 
point  burnisher  to  enable  it  to  better  resist  the  aggressive  force 
of  the  lower  teeth.  The  third  molars  were  capped  and  length- 
ened with  gold  crowns,  the  lines  of  their  sides  being  made 
parallel,  to  admit  of  a  proper  adjustment  of  the  supporting  collars 
for  a  removable  plate  bridge,  by  adding  gold  on  their  external 
surfaces.  The  plate  bridge  was  employed  because  of  the  space 
between  the  abutments,  which  suggested  the  idea  of  utilizing 
the  alveolus  to  assist  in  supporting  it.  A  narrow  shoulder  was 
formed  on  each  crown  to  support  the  collars.  The  attachments 
to  the  cuspids  rested  by  means  of  a  little  shoulder  on  the  occlud- 


OPERATIVE  DENTISTRY  WITH  CRO  WN-  AND  BRIDGE-  WORK.    319 


ing  portions  of  the  fillings  inserted.     Fig.  617  shows  the  com- 
pleted denture,  and  Fig.  618  an  anterior  view  of  the  same.1 


Fig.  617. 


In  the  case  illustrated  in  Fig.  619,  the  patient,  a  lady,  had 
previously  worn  a  plate,  the  clasp  of  which  had  entirely  abraded 
the  sides  and  cervix  of  the  right  cuspid  of  enamel,  and  caused 
recession  of  the  margin  of  the  investing  gum.     The  decay  which 

Fig.  618. 


followed  the  abrasion  extended  in  a  circle  around  the  tooth.  As 
the  patient  objected  to  crowns  of  any  kind  being  applied  to 
either  of  the  cuspids,  the  decay  was  removed  and  the  edges  of 
the  cavity  given  a  retaining  form.     A  gold  filling  was  then  intro- 

1  Case  operated  on  in  1888. 


320 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


(laced  in  three  sections,  two  of  which  embraced  the  approximal 
and  palatal  sides,  while  the  third  surrounded  the  labial  wall, 
joining  the  other  two  sections  at  that  point,  the  three  thus  com- 
pletely encircling  the  tooth  with  gold.     A  portion  of  the  filling 

Fig.  619. 


was  brought  over  the  edges  of  the  cavity  to  better  shape  the 
tooth  for  the  attachment  to  be  applied  and  also  to  protect  the 
sides  from  future  injury.  When  this  operation  was  completed, 
the  tooth  presented  very  much  the  appearance  of  having  had  a 
close-fitting  shell  crown  applied.     Gold  fillings  were  introduced 

Fig.  620. 


in  the  palatal  and  approximal  surfaces  of  the  left  cuspid,  to  pro- 
tect it  from  the  attachment.  Gold  crowns  were  placed  upon  the 
molars,  one  of  which,  the  left,  was  pulpless.  The  appearance 
of  the  teeth  after  these    perations  is  shown  in  Fig.  620. 


OPERATIVE  DENTISTRY  WITH  CROWN-  AND  BRIDGE-WORK.  321 

A  plate  bridge  (Fig.  621)  was  then  constructed,  the  attachments 
for  which  were  collars  on  the  molars,  and  half-collars  or  clasps 
on  the  cuspids.  The  former  rested  on  shoulders  formed  on  the 
gold  crowns,  and  the  latter  on  the  palatal  curves  of  the  cuspids.1 

Fig    621. 


Fig.  622  illustrates  a  case  as  presented  for  treatment  to  Dr. 
H.  A.  Parr.  The  loss  of  the  posterior  teeth  of  the  lower  jaw 
and  the  abrasion  of  the  anterior  teeth  had  resulted  in  the 
abnormal  occlusion  shown.  The  incisive  edges  of  the  lower 
teeth  were  lengthened  with  gold  contour  fillings.  Gold  collar 
crowns  with  porcelain  fronts  were  placed  on  the  upper  anterior 
teeth,  to  lengthen  them  sufficiently  to  restore  the  occlusion.  The 
upper  molars,  which  were  all  more  or  less  decayed  and  broken 

Fig.  622. 


down,  were  restored  in  form  with  gold  crowns.  The  space 
representing  the  loss  of  the  left  bicuspid  was  filled  with  a  bridge 
tooth  having  a  porcelain  front,  attached  to  the  approximal  gold 
crown.     In  the  lower  jaw  a  partial  set  was  inserted  on  each  side 

1  Case  operated  on  in  '  <8y. 
22 


322  ARTIFICIAL  CROWS-   A  SD   BRIDGE- WORK 

to  substitute  the  lost  posterior  teeth.     Fig.  623  shows  the  appear- 
ance of  the  case  when  completed. 

The  following  case  is  a  marked  illustration  of  extensive  con- 
tour tilling  combined  with  gold  and  porcelain  crown-work.  The 
operations  were  performed  by  Dr.  E.  P.  Brown,  with  the  excep- 

Fio.  6-23, 


tion  of  the  porcelain  inlays,  which  were  inserted  by  Dr.  C.  H. 
Land.  Fig.  624  represents  the  case  before  treatment.  The  teeth 
show  the  effects  of  erosion,  abrasion,  and  decay.  The  upper 
teeth  at  the  incisive  and  palatal  portion  were  contoured  with 
rolled  gold,  Xo.  60,  condensed  with  the  Bonwill  electric  mallet. 
A  porcelain  crown  was  placed  on  the  root  of  the  left  cuspid,  and 
a  gold  crown  on  the  first  left  bicuspid.  The  eroded,  decayed, 
and  abraded  portions  of  the  other  bicuspids  were  contoured  with 
gold.  The  treatment  of  the  lower  teeth  consisted  in  contouring 
with  gold  the  abraded  occluding  surfaces  of  the  right  first  and 
second  bicuspids  and  left  first  bicuspid.  The  left  second  bicuspid 
and  two  right  molars  were  crowned  with  gold.  The  cervical 
decay  which  affected  the  inferior  right  lateral,  cuspid,  and  first 
bicuspid  and  left  cuspid  was  removed  and  inlaid  with  sections 
of  porcelain  colored  with  gum  enamel  at  the  line  of  the  gum- 
margin  by  Dr.  Land.  Fig.  625  shows  the  superior  arch  from 
the  palatal  aspect  when  completed.  Fig.  626  is  a  labial  or  front 
view  of  the  several  operations.1 


1  The  patient,  Dr.  W.  I.  Thayer,  exhibited  these  operations,  nearly  completed, 
at  the  clinic  of  the  First  District  Dental  Society  of  New  York,  February,  1889. 


OPERATIVE  DENTISTRY  WITH  CROWN-  AND  BRIDQE-WORK.  323 

Fig.  624. 


Fig.  625. 


Fig.  626. 


PAET  IV. 

MATERIALS  AND  PROCESSES  USED  IN  CROWN-  AND 
BRIDGE-WORK. 


CHAPTER   I. 

PLATE  AND  SOLDERS. 

Plate. — In  the  construction  of  crown-  and  bridge-work,  gold, 
platinum,  or  iridio-platimim  is  used  in  the  following  forms  and 
grades  in  carat,  as  suits  the  requirement  of  the  case  and  the 
preference  of  the  dentist: 

Gold  plate,  24  carats,  from  No.  30  to  Xo.  34  IT.  S.  standard 
gauge,1  for  constructing  the  collars  and  caps  to  collars  of  crowns 
and  seamless  crowns,  and  for  backing  porcelain  fronts. 

Gold  plate,  slightly  alloyed, — about  23  carats  fine, — in  crown- 
work,  if  less  flexibility  of  the  metal  is  required. 

Gold  plate,  22  carats,  No.  31  to  No.  32  standard  gauge,  in 
constructing  collars  for  crowns  with  porcelain  fronts  and  all-gold 
crowns  made  in  sections. 

Gold  plate,  20  carats,  in  construction  of  bridge-Avork. 

Gold  for  constructing  collars  should  be  of  as  high  a  carat  as 
possible,  to  better  resist  the  action  of  acids.  A  large  proportion 
of  copper  as  an  alloy  is  objectionable,  owing  to  its  tendency  to 
cause  tarnishing  of  the  collar  where  an  acid  condition  of  the 
saliva  exists.  For  this  reason,  United  States  gold  coin,  contain- 
ing 10  per  cent,  copper,  so  much  used  for  collars,  is  not  quite 
suitable.  It  is  also  too  stiff,  and  collars  made  of  it  are  not  readily 
burnished  to  fit  at  the  edges.  Dr.  J.  J.  R.  Patrick's  formula, 
which  is  equal  parts  of  coin  and  pure  gold,  affords  a  plate  which 
is  decidedly  preferable,  inasmuch  as  the  proportion  of  copper  is 
reduced  to  5  per  cent. 

Gold  plate,  24  carats,  with  a  very  thin  lining  of  platiuum  or 
iridio-platinum  plate,  can  be  used  in  any  of  the  processes  con- 
nected with  crown-  and  bridge-work,  and  is  especially  recom- 
mended to  the  inexperienced,  for  the  reason  that  the  melting  of  a 
part  of  a  crown  in  the  soldering  process  is  prevented  by  its  use. 

'The  United  States  standaid  is  the  only  gauge  referred  to  in  the  original 
descriptive  matter  of  this  treatise. 

327 


328  ARTIFICIAL   CROWN-  AND  BRIDGE- WORK. 

It  is  formed  by  placing  together  an  annealed  gold  plate  and  a  plat- 
inum plate  (the  gold  about  Xo.  20  gauge  and  the  platinum  No. 
30)  and  passing  them  through  a  rolling-mill,  in  which  process  the 
plates  are  welded  and  reduced  to  the  desired  thickness. 

Platinum  and  iridio-platinum  plate  is  used  for  forming  crowns 
for  use  in  connection  with  porcelain  bridge-work.  Iridio-plat- 
inum plate  for  forming  small  collars  need  not  be  over  No.  35 
gauge.  At  this  thickness  it  can  be  easily  adapted  to  the  cervix 
of  the  tooth. 

Pure  platinum  rolled  very  thin  is  used  for  forming  caps  to 
collars,  backing  teeth,  and  for  various  purposes  connected  with 
this  class  of  operations.  Iridio-platinum  wire  is  used  for  pivots, 
pins,  or  posts,  being  more  rigid  than  pure  platinum.  A  wire 
of  gold  and  platinum  alloy  is  used  on  account  of  its  elasticity 
for  split  or  spring  pivots  or  posts  in  removable  bridge-work. 

Solders. — Gold  solder,  22  carats  fine,  is  used  for  crown-work; 
20  carats  for  crown-  and  bridge-work. 

18  carats  is  used  for  crown-  and  bridge-work,  but  this  is  con- 
sidered by  some  too  low  a  carat. 

14  carats  for  strengthening  seamless  crowns;  used  only  in 
crowning  operations. 

Successive  grades  of  solder  from  hard  to  easy  flowing  can  be 
used  in  the  regular  soldering  of  crown-  and  bridge-work;  gold 
plate  or  a  hard-flowing  solder  for  the  first,  a  medium-flowing  sol- 
der forthe  next,  and  an  easy-flowing  one  for  the  finish.  This  avoids 
melting  or  flowing  of  the  gold  at  any  point  previously  soldered. 

Any  grade  of  solder  can  be  made  according  to  the  following 
formula : 

Zinc,  H  grs. ; 
Pure  gold, 

Silver  solder,  in  quantity  sufficient  to  make  up  the  22£ 
remaining  parts  in  weight. 

The  quantity  of  silver  solder  used  will  regulate  the  grade  in 
carat  of  the  solder.     Thus  : 

Zinc,  \\  grs.  ; 
Pure  gold,  20  grs.  ; 
Silver  solder,  3  grs., 

will,  by  the  burning  out  of  a  portion  of  the  zinc  in  the  process, 
make  a  solder  about  20  carats  fine. 


PLATE  AND  SOLDERS.  329 

By  lessening  the  proportion  of  zinc  from  1^  grains  to  1  grain, 
the  proportion  of  silver  solder  being  kept  the  same,  the  solder 
will  become  harder-flowing  and  a  little  finer. 

Dr.  W.  H.  Dorrance  recommends  the  following  formula  as  an 
alloy  for  the  formation  of  different  grades  of  gold  solders,  the 
proportion  of  the  alloy  used  determining  the  melting-point  and 
fineness  in  carat  of  the  solder : 

1  part  pure  silver; 

2  parts  pure  zinc  : 

3  parts  pure  copper. 

The  silver  and  copper  are  first  melted  together  in  a  crucible 
lined  with  borax,  and  the  zinc  added  quickly  in  small  pieces, 
stirring  the  mass  meantime  with  a  pipe-clay  stem.  It  is  then, 
on  the  fumes  of  the  zinc  passing  off,  immediately  poured  into 
an  ingot-mold  or  into  a  large  wooden  pail  filled  with  water ; 
4  grains  of  this  alloy  melted  with  20  grains  of  pure  gold  will 
result  in  a  solder  fully  20  carats  fine. 

As  a  solder  for  crown-  and  bridge-work  constructed  of  22- 
carat  gold  plate,  Dr.  Litch's  formula  is  as  follows : 

Gold  coin  (ten  dollars),  258  grs. , 
Spelter  (or  brazier's  solder),  24  grs. ; 
Silver  coin,  24  grs. 

This  is  a  proportion  of  about  26  grains  of  pure  copper  and  232 
grains  of  pure  gold  to  the  remaining  48  grains  of  the  alloy,  and 
makes  a  good  solder  a  little  over  18  carats  fine. 

Dr.  C.  M.  Richmond  originally  used  American  gold  coin  for 
forming  gold  crowns,  rolling  it  out  in  the  form  of  plate.  The 
scraps  he  formed  into  solder  by  melting  and  adding  one-fifth 
of  their  weight  of  fine  brass  wire  cut  in  small  pieces,  using 
plenty  of  borax. 

Dr.  Low's  formula  for  solder  in  bridge-work  is  : 

1  dwt.  coin  gold  ; 

2  grs.  copper ; 

4  grs.  silver. 

This  makes  a  solder  about  19  carats  fine. 


330  ARTIFICIAL  CRO  WN-  AND  BRIDGE-  WORK. 

The  following  formula1  gives  a  20-carat  solder  which  is  specially 
recommended  for  crown-  and  bridge-work  : 

American  gold  coin  (21.6  carats  fine),  $10  piece,  268  grs.  ; 
Spelter  solder,  20.64  grs. 

Fluxed  Solder  Filings. — Fluxed  gold  solder  filings  are  made 
by  filing  with  a  clean,  flat  plate  file  a  thick  piece  of  solder  held 
in  a  vise.  The  filings  are  allowed  to  fall  in  a  box  or  on  a  sheet 
of  paper  placed  to  receive  them.  A  magnet  should  be  passed 
through  the  filings  to  remove  any  minute  particles  of  steel. 
To  five  parts  of  the  filings  so  made  is  added  and  well  mixed 
with  them  one  part  of  the  prepared  flux  or  finely  pulverized 
vitrified  borax.  Solder  prepared  in  this  way  is  useful  for  strength- 
ening crowns,  and  also  in  fine  soldering  operations,  as  the  parti- 
cles of  the  solder  take  the  heat  separately  and  fuse  much  more 
quickly  than  when  the  solder  is  cut  in  pieces.  The  flow  of  the 
solder  is  also  more  easily  limited. 

1  American  System  of  Dentistry,  vol.  iii,  p.  84°. 


CHAPTER    II. 

PORCELAIN   TEETH. 

The  qualities  specially  requisite  in  the  body  of  porcelain  teeth 
for  use  in  crown-  and  bridge-work  are  density,  strength,  and  the 
ability  to  withstand  unaltered  in  form  or  shade  any  degree  of  heat 
to  which  they  may  necessarily  be  subjected.  In  these  respects 
the  porcelain  teeth  of  our  best  American  manufacture  seem  to 
excel,  besides  affording  the  most  artistic  imitation  of  the  natural 
teeth  in  form  and  shade.  They  are  also  distinguished  by  the 
practical  location  of  the  pins. 

In  some  crowning  operations,  where  to  imitate  the  conforma- 
tion of  a  natural  crown  considerable  alteration  of  the  labial 
surface  of  a  porcelain  front  is  required,  teeth  of  English  manu- 
facture may  be  used,  as  the  texture  of  the  porcelain  admits  of  a 
tine  polish  being  given  to  a  ground  surface. 

Teeth  are  sometimes  fractured  in  the  process  of  soldering, 
caused  by  the  contraction  of  the  backing  when  adapted  over 
the  edges  of  the  porcelain  in  a  curve  instead  of  at  a  right  or 
slightly  obtuse  angle,  or  by  melting  solder  on  some  point  of  the 
porcelain  which  is  unprotected  by  a  backing  of  metal.  The 
solder,  or  the  borax,  as  it  cools,  contracting  on  the  porcelain,  or 
a  very  thin  edge  of  the  metal  covering  it,  will  usually  cause  a 
fracture.  The  porcelain  tooth  has  yet  to  be  made  that  will,  as  a 
rule,  endure  such  extreme  treatment  without  breaking. 


331 


CHAPTER    III. 

MOLDS  AND  DIES. 

Metallic  models  of  fusible  metal  can  be  easily  and  quickly 
formed  for  use  in  crown-  and  bridge-work.  The  melted  alloy 
can  be  poured  into  a  plaster,  moldine,  or  gutta-percha  impression 
taken  in  a  tube  or  impression-tray.  AVhen  a  tube  is  used,  a  strip 
of  paper  should  be  wound  around  it  to  lengthen  the  die. 

The  following  fusible  alloys  of  tin  are  suitable  for  the  purpose  : 

PROPORTIONS  OF  METALS.  MELTING  POINT  OF 

THE  ALLOT. 

Tin.  Lead.  Bismuth.  Fahr. 

1  2  2  236° 

5  3  3  202° 

3  5  8  197° 

Dr.  G.  W.  Melotte,  of  Ithaca,  N.  Y.,  to  whom  is  accorded  the 
credit  of  introducing  the  use  of  fusible  metal  and  the  compound 
called  "  moldine"  into  crown-  and  bridge-work,  gives  the  propor- 
tions of  his  alloy  in  {Darts  as — 

Tin,  5;  Lead,  3;  Bismuth,  8. 

Dr.  Melotte's  moldine,  a  preparation  compounded  of  potter's 
clay  and  glycerin  (to  which,  when  needed  to  soften  it,  more 
glycerin  can  be  added),  is  very  useful  in  molding. 

HOW  TO  QUICKLY  MAKE  A  TUBE  AND  FUSIBLE  METAL  DIE. 

Take  a  thin  strip  of  copper  plate,  at  least  35  gauge,  anneal,  and 
bend  it  around  the  tooth  in  the  mouth  or  its  form  on  the  plaster 
model.  Both  ends  of  the  copper  at  the  part  lapped  are  next  cut, 
as  shown  at  A,  Fig.  627,  and  turned  over  tight  and  close  in  the 
manner  seen  at  B.  This  fastens  both  ends  of  the  copper,  which 
when  trimmed  oft'  at  C,  forms  a  tube.  In  this  tube,  with  a  little 
impression  compound,  gutta-percha,  or  moldine,  take  an  impres- 
sion of  the  natural  crown  either  in  the  mouth  or  from  the  plaster 
model  by  trimming  around  the  tooth  or  by  separating  it  from 

332 


MOLDS  AND  DIES.  333 

the  rest  of  the  model.     Encircle  the  tube  with  a  strip  of  paper. 
Hold  the  paper  and  tube  with  a  clamp.     Melt  and  pour  the 
fusible  metal  moderately  cool,  and  immerse  tube  and  metal  in 
water.     This  gives  a  die  with  a  long  narrow  shank, 
which  may  require  to  be  trimmed  at  the  neck  with  a 
file.     When  impression  compound  or  gutta-percha  is 
used,  cool  and  then  dry  the  surface  with  an  air  syringe 
before  pouring  the  fusible  metal. 

A  counter-die  to  a  small  cast  or  die  of  fusible  metal 
is  made  by  indenting  a  block  of  lead  with  a  punch,  and 
then  driving  the  cast  or  die  into  it.     Its  use  in  crown- 
work  is  described  on  pages  93,  102,  and  106,  and  by   I 
Dr.  Melotte  on  page  276. 

The  following  method  of  forming  a  metallic  model 
of  a  prepared  root  or  crown  is  given  by  Dr.  TV.  C.  Barrett,  of 
Buffalo,  X.  Y.,  who  accords  Dr.  H.  A.  Baker,  of  Boston,  the 
credit  of  being  the  originator  of  it : 

"  Copper  is  rolled  down  quite  thin,  and  a  band  three-fourths 
of  an  inch  wide  wrapped  about  the  root  and  forced  up  under 
the  gum.  A  ligature  is  passed  around  both;  the  copper  band 
is  burnished  down  and  the  ligature  drawn  tight.  The  copper 
band  will  now  fit  just  as  we  want  the  gold  band  to  do.  Plaster 
of  Paris  is  then  inserted  in  this,  forced  up  against  the  end  of 
the  root,  and  permitted  to  set.  Take  it  oft',  and  if  you  use 
Babbitt-metal,  a  piece  of  paper  wrapped  about  it  (the  copper 
band)  will  lengthen  it  out  sufficiently,  when  the  metal  may  be 
poured  into  it,  and  thus  a  perfect  model  of  the  end  of  the  root 
will  be  secured.  That  part  which  is  inserted  in  the  copper  tube 
is  the  exact  reproduction  of  the  root  of  the  tooth.  The  model 
will  perhaps  need  a  little  dressing  down  with  a  file,  when  the 
gold  band  may  be  fitted  around  it  and  soldered,  thus  avoiding 
the  necessity  for  the  annoying  and  painful  trying-on  in  the 
mouth." 

Fusible  metal  can  be  used  instead  of  Babbitt-metal. 

Dr.  Melotte  has  lately  introduced  for  special  cases  a  novel 
method  of  forming  a  combination  plaster  and  metal  model,  in 
which  the  parts  representing  the  teeth  are  of  fusible  metal. 
The    following  is  a   description:    The  impression  is  taken  in 


334  ARTIFICIAL  CROWN-  AND  BRIDOE-WORK. 

plaster.  Iron  pins  to  act  as  dowels  are  placed  in  the  molds  of 
the  teeth.  Pieces  of  a  fusible  metal,  which  melts  at  a  low  point, 
are  then  melted  into  each  of  the  molds  with  a  few  puffs  of  the 
blow-pipe.  Plaster  is  then  poured  in  the  remainder  of  the 
impression.  The  advantage  afforded  by  a  model  of  this  kind, 
when  gold  attachments  or  clasps  are  to  be  shaped  to  teeth,  is 
obvious.  The  method  applied  in  the  construction  of  bridge- 
work  is  given  on  page  161.  Dr.  Melotte'a  formula  for  the 
fusible  metal  used  in  the  above  method  is: 

Bismuth,    8  parts ; 
Lead,  4      " 

Zinc,  3      " 

Cadmium,  2      " 
Melt<  at  about  150°  P. 


Fig.  628. 


CHAPTER    IV. 

SOLDERING. 

Investments  for  soldering,  and  models 
on  which  the  soldering  is  to  be  done  for 
bridge-work,  are  made  of  calcined  mar- 
ble-dust and  plaster,  in  the  proportion 
of  equal  parts  for  models,  and  one  part 
of  plaster  to  two  of  marble-dust  for 
investing;  or  one  part  plaster,  one  cal- 
cined marble-dust,  and  one  of  common 
white  sand.  If  the  investment  is  large, 
an  iron  wire  should  be  passed  through 
or  around  it  in  the  material.  Sulphate 
of  potassium,  used  in  place  of  common 
salt,  but  in  smaller  quantity,  will  cause 
the  mixture  to  set  quickly  and  hard. 

Soldering. — In  soldering  crown- and 
bridge-work  or  sections  of  it  containing 
porcelain  fronts,  the  investment  should 
be  first  uniformly  and  thoroughly 
heated,  and  the  heat  maintained  during 
the  process  of  soldering.  This  is  espe- 
cially necessary  in  the  final  soldering  of 
gold  crowns  with  porcelain  fronts,  as 
the  solder  is  thereby  flowed  into  the 
interstices  between  the  porcelain  and 
the  caps,  and  gives  continuity  of  struc- 
ture to  the  crown.  A  large  piece  of 
charcoal,  concave  on  the  side  to  be  used, 
and  the  other  side  invested  with  a  thin 
covering  of  plaster,  furnishes  a  good 
soldering  support,  as  it  retains  the  heat. 
A  hand  gas  blow-pipe,  operated]  by  a 


335 


336  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

foot  bellows,  and  so  constructed  that  the  flame  is  under  perfect 
control,  is  the  most  suitable  (Fig.  628). 

The  Use  of  Borax. — In  soldering  invested  sections  of  a  crown  or 
bridge  together,  borax  which  has  been  reduced  to  a  vitreous  state 
by  heat  and  then  finely  pulverized  is  the  preferred  form  for  its  use. 
Prepared  in  this  manner  it  should  be  sprinkled  on  the  part  pre- 
vious to  the  commencement  of  the  soldering,  and  a  little  added 
at  any  time  it  is  needed  during  the  continuance  of  the  process.1 

In  small,  fine  soldering  of  invested  or  uninvested  work,  the 
lump  borax  ground  with  water  on  a  slab  to  a  cream-like  con- 
sistence and  applied  with  the  point  of  a  stick  or  brush  only 
where  it  is  desired  to  have  the  solder  flow,  is  the  most  suitable. 

1  Dr.  Parr's  "  prepared  flux,"  a  finely  pulverized  vitrified  flux,  can  be  used  in 
this  manner.  It  is  conveniently  kept  in  the  form  of  a  saturated  solution  in  a 
bottle,  from  which  the  operator  can  use  it  with  a  brush  or  stick  in  fine  solderings. 

It  is  also  prepared  in  combination  with  wax  cement.  In  the  melting  out  of  the 
wax  when  the  case  is  invested  and  heated  for  soldering,  the  flux  is  carried  into 
the  interstices. 


CHAPTER  V. 

INSTRUMENTS  AND  APPLIANCES. 

The  dentist  who  intends  to  eno-a^e  extensively  in  crown-  and 
bridge-work,  and  who  desires  to  practice  it  conveniently  and  suc- 
cessfully, should  supply  himself  with  all  the  necessary  instru- 
ments, tools,  and  other  appliances.     These  consist  principally  of 

Fig.  629 


drills  of  various  styles,  among  them  the  Grates-Glidden  for  root- 
canals;  root-trimming  and  shaping  instruments;  corundum- 
wheels  and  points  ;  rubber  and  corundum  disks  ;  suitably  shaped 
pliers;  clamps  of  various  forms  for  use  in  the  many  soldering 
processes;  some  moldine  and  fusible  alloy,  and  dies  for  forming 
gold  caps  for  use  in  constructing  crowns  and  capping  dummies  : 

23  •  337 


338 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


a  Lee  blow-pipe  or  Knapp's  compound  blow-pipe,  or  both,  for 
use  as  is  most  suitable  or  convenient. 

The  bench  on  which  the  principal  parts  of  the  work  are  done 
should  be  specially  designed  and  reserved  for  it.  It  should  be 
in  the  same  room,  and  conveniently  situated  a  little  behind  the 
dental  chair,  out  of  view  of  the  patient.     Everything  connected 

Fio.  fi.so 


with  this  bench  should  be  kept  in  order  and  ready  for  immediate 
use.  Such  a  bench,  made  of  black  walnut,  with  a  top  that  can 
be  closed  when  not  in  use,  making  an  unobjectionable  piece  of 
furniture,  is  represented  in  Figs.  629  and  630. 

An  office  lathe  should  be  kept  next  to  the  bench,  or  a  small 
lathe-head  can  be  mounted  on  the  bench  and  operated  by  the 
aid  of  an  electric  motor. 


IKDEX. 


Abrasion  of  incisive  edges  of  teeth,  101 
method  of  forming  crown  for,  100, 123 

199,  284,  243,  315,  317,  321 
Abscess,  chronic  alveolar,  treatment  of 

28 
Acid,  arsenious,  its   use  and   action   in 

devitalizing  pulps,  18 
Acid    secretions,    platinum    unaffected 

by,  104,  124 
Adaptation  of  gold  collars,  83,  113 

of  porcelain  crowns,  method  of,  43 
Adjuster    for    use    in    cementation  -of 

crowns,  147 
Adjustment  of  finished  bridge-work  in 

the  mouth,  168 
Advantages     of    a    flange   to    support 

crown,  78,  104 
Alloy  for  forming  any  grade  of  gold 

solder,  328 
Alloys  of  tin,  their  use  in  crown-work, 

332 
Alveolar  abscess,  classification  of,  28 

treatment  of,  28 
Ames's  method  of  forming  gold  tips,  139 
Amputation  of  the  apex  of  a  root,  31 
Analysis  of  dentine,  12 
Anatomical  structure  of  dentine,  10 
Anchorage    bars    in    bridge-work,    139. 

160,  173,  182,  241,  305 
manner  of  attaching  to  the  abutments, 

160,  169,  183,  310 
manner  of  forming,  160,  183,  185,  260, 

305 
Anchorages   or  abutments   for  bridge- 
work,  preparation  of,  158,  172,  174, 

177,  179,  183,  189,  279 
Dr.  Litch's  method,  241 


Anchorages   or  abutments    for  bridge- 
work.  Dr.  Parr's  method,  248 
Dr.  Winder's,  238 
shell,  175 
Ancient  bridge-work,  153 
Anesthesia  in  pulp-extraction,  16 
Anesthetics,    local,    for    application    to 
gum,  29,  31,  84 
use  of  in  crown-work,  84 
Antagonizing  teeth,  preparation  of  their 

cusps,  36 
Antiseptic  agents  in  treatment  of  alveo- 
lar abscess,  29,  31 
in  treatment  of  pulpless  teeth,  25 
Anvil,  use  of  in  crown-work,  83,  114 
Aristol,  use  of  in  pulp-canal,  25 
Arsenious  acid,  use  of  in  devitalization 

of  the  pulp,  17,  18 
Articulation   for  bridge-work,   manner 

of  taking,  160 
Artificial  crown-work,  5,  39 
the  gold  system,  77 
the  porcelain  system,  42 
Artificial  gum  in  porcelain  bridge-work, 

230,  311,  312 
Attachments  for  removable  bridge-work, 
209,  225,  238,  242,  245,  248,  250, 
256,  260,  318,  321 

Backings  for  porcelain  fronts  in  crown- 
work,  86,  163,  165,  166,  321,  328 
Baldwin's  method  of  mounting  crowns. 

70 
Bar  bridge-work,  160,  172,  182,  241,  285, 
305 
advantages  of,  186 
anchoring  of  the  bar,  183. 

339 


340 


I.XDEX. 


Bar  bridge-work,  cast  tilling  to  support, 
186 
extension,  185,  191,  260 
in  bicuspids  and  molars,  184 
in  incisors  and  cuspids,  182 
Bars  for  bridges,  139,  160,  183,  185,  186, 

314 
Beers's  crown,  79 
Bing's  bridge-work,  154 
Blind  abscess,  treatment  of,  29 
Blow-pipes,  Lee's,  335 

Knapp's  carbo-oxyhydrogen,  273 
Bonwill's  porcelain  crowns,  43 
Borax,  method  of  using  in  crown-  and 
bridge-work,  in  constructing  root- 
caps  and  tubes,  210,  336 
Bridge-work,  153 
adjustment  and  insertion,  168 
an  impartial  criticism  of,  155,  206 
as  affecting  hygienic  condition  of  the 

mouth,  206 
cantilever,  180 
cases   illustrating  the  application  of, 

189,  315 
cementation  of,  145,  168,  177,  184 
construction  of,  158,  169,  171 
detachable,  238,  241,  246,  248 
extension,  178 

extensive  application  of,  193 
foundations  for,  158 
general  application  of,  189 
manner  of  taking  impression  and  ar- 
ticulation   for,    160,   161,  169,  179, 
218,219,  222,  333 
mechanical  principles  governing  the 
process   of  construction,    158,   181, 
182 
method  versus  to  forming  self-cleans- 
ing spaces,  165 
methods  in  pyorrhea,  193 
partial  cap  and  pin,  175,  177,  179,  193, 

279 
plate,  225,  305 
porcelain,  305 
removable,  208 
removal  of,  204 
selection  of  abutments,  158,  181 


Bridge-work,  special  processes  and  ap- 
pliances in,  171 
with    replaceable    porcelain     fronts, 
187 
Brown's  bridge-work,  305 
gold  crown,  99 
porcelain  crowns,  63 
Burnishers  for  adapting  collars,  84 
use  of  in  crown-work,  83,  112 

Cantilever  bridge-work,  180 

crown,  135 
Cap  for  collar,  to  construct,  85 
Capping  pulps,  methods  of,  13 
Cast  fillings,  139 

to  support  bridge-work,  186 
Cement,  amalgam,  gutta-percha,   oxy- 

phosphate,  145,  148 
Cement,   to  cause  oxyphosphate,  to  ad- 
here to  tooth-structure,  177 
to  cause  to  set  slowly,  146 
Cementation  of  crown-  or  bridge-work, 

145,  168,  177 
Chronic  alveolar  abscess,  28 
Circulation  in  dentine,  10 
Clamps,  soldering,  83,  93,  94,  172,  276 
Cleansing  of  bridge-work  when  worn  by 

patients,  207 
Cocaine,  use  of,  16,  18,  31,  84 
Collar  contractor,  83,  115,  290 
crowns   hygienically   considered,  66, 

124 
pliers,  80,  113,  292 
Collar  crowns,  79 

bicuspids  and  molars,  88,  92,  104,  108 
incisors  and  cuspids,  85,  100,  102,  119 
Collars,  method  of  adaptation  of  seam- 
less crowns,  112,  113,  114,  115 
to  solder,  82 
Collars  for  crowns,  79,  291 

construction    and    adaptation  of,   79, 

289 
Townsend's  fusible  die  in  forming,  68 
Connecting   bars   in    bridge-work,   173, 

186,  191,  216,  253 
Construction  of  bridge-work,  158,  169, 
171 


INDEX. 


341 


Construction  of  bridge-work  : 

bar,  182,  305 

detacbable  and  removable,  208,  217. 
238 

mechanical  principles  governing,  158, 
181,  182 

plate,  225,  305 

saddles,  178,  196,  221,  224 

small  pieces  of,  169 

special  processes  and  appliances  in, 171 
Corundum-wheels  and  points,  33,  34 
Crown-  and  bridge- work  combined  with 
operative  dentistry  in  dental  pros- 
thesis, 315 

instruments  and  appliances,  337 
Crowns,  artificial : 

Baldwin's  method  of  mounting,  70 

Bonwill,  43 

Bonwill  cap,  71 

Brown,  63,  99,  305 

Evans  gold,  108 

Farrar's  cantilever,  135 

Fillebrown's,  99 

Foster,  57 

Gates,  56 

How,  49 

Howland,  57 

Kirk's  method  of  mounting,  70,  148 

Leech,  127 

Logan,  58 

Low,  128 

New  Richmond,  64 

Parker's,  107 

Parr,  126 

Patrick,  99 

Perry,  130 

Richmond,  85 

Rynear,  99 

Simplicity,  72 

Stowell's  method  of  mounting,  90 

Van  Woert,  78 

Weston,  73 

all-gold,  in  sections,  92 

attachments  for  all-gold  and  seamless 
gold,  37,  117,  118 

cementation,  process  of,  145 

contouring  of  collars,  92 


Crowns,  countersunk,  94 

dies  for  use  in  construction  of,  89,  93, 

96,  102,  106,  107,  118,  120,  332 
expanding,  83,  112 
finishing  and  polishing,  145 
for  abraded  teeth,  101,  123,  315 
for  separate  molar  roots,  284 
gold   and   porcelain,   for   teeth    with 

living  pulps,  119 
gold  and  porcelain,  without  a  collar, 

77 
gold  collar,  79,  287 
gold  seamless  cap,  102,  108 
gold  seamless  contour,  108 
mandrel  system,  2S7 
partial,  137 

porcelain,  with  collar  attachment,  68 
porcelain,    with    rubber    attachment, 

76 
preparation  of  crown  or  root  for,  9, 

33 
process  of  adjustment  of  gold  contour, 

seamless,  111 
remarks  on  the  use  of  collar  or  porce- 
lain crowns,  66,  124 
removal  of,  204 
repair  of,  202 
shell,  175,  179,  193 
Curtis  removable  bridge,  262 
Cusps  of  antagonizing  teeth,  preparation 

of,  36 

Davenport   removable     plate    bridge- 
work,  234 
Decayed  roots,  special  preparation  of  for 

crown-work,  36 
Dentine,  circulation  in,  10 

chemical  analysis  of,  12 
Detachable  bridge-work,  238,  241,  245, 

248 
Detachable  porcelain  front,  187 
Devitalization  of  pulps,  10,  Hj 

heroic  or  instantaneous,  16 

instant,  16 

use  of  arsenic  for,  17,  18 

use  of  cocaine  in,  16 
Die-plate,  95 


342 


INDEX. 


Dies,  89,  93,  96,  102,  106,  107,  118,  120, 
332 
Dr.  Baker's  method,  333 
Dr.  Melotte's  method  for  forming,  332 
counter,  103,  106,  333 
fusible  metal,  332,  334 
Diseased  pulps,  classification  of,  requir- 
ing extirpation,  12 
Diseased  teeth  or  roots,  badly,  9 

with  necrosis  of  alveoli,  9 
Disinfection  of  root-canals  and  dentine, 

24,  25,  26 
Disks,  forms  of,  34 
Drills,     Gates-Glidden,    form    of     and 

method  of  using,  22 
Dummies,  definition  of,  165 
Dwinelle's  crown,  79 

Enameling  gold  crowns,  method  of,  122 
English  bridge  work,  154 
Evans  gold  crowns,  108 

method  of  constructing  dummies  in 
bridge- work,  164 

non-fusible  crown,  108 
Excision  of  crown,  16,  35 

and  instantaneous  extirpation  of  the 
pulp,  16 

when  to  avoid,  12 
Expansion  of  a  collar  or  crown,  83,  112 
Extension  bar-bridge,  185,  310 
Extension  bridges,  178 

leverage  in,  180 
Extirpation  of  pulps,  16,  17,  18 

Facing,  glas$ ,  for  gold  crowns,  122 
Farrar's  cantilever  crown,  135 
Ferrules  for  root- crowns,  79,  291 
Files  for  trimming  roots  or  crowns,  34 
Fillebrown's  crown,  99 
Filling  of  root-canals,  26 
Finishing   and    polishing  bridge-work, 
167 

crown-work,  145 
Flange  to  better  >. support  a  gold  crown, 

78, 102 
Forceps  for  excising  crowns,  17 

for  repairing,  202 


Formulas  for  fusible  metals,  332,  334 

for  gold  solders,  327 
Foster  crown,  57 

Foundations  for  bridge-work,  158 
Fracture  of  porcelain  teeth  in  soldering, 

331 
Fractured  teeth  and  roots,  treatment  of 

for  crowning,  132 
French  bridge-work,  154 
Fusible  alloys  of  tin,  332 

Melotte's,  332,  334 

Gartrell  bridge,  260 

Gates  crown,  56 

Gold,  all-,  crowns  for  front  teeth,  100 
solid,  116,  172 

Gold  collar  crowns,  79,  287 

preparing  natural  teeth  for,  9,  33 

Gold,  method  of  using,  85,  327 

Gold  plate  lined  with  platinum,  327 
crown-metal,  80,  327 
solder  filings,  80,  115,  330 
solders,  formulas  for,  328,  329 
standard  of  carat  and  gauge  required, 

85, 327 
tips  for   natural   crowns,   method   of 

constructing,  139 
wire,  328 

Gutta-percha    for    forming    molds    of 
crowns  or  roots,  102 
in  filling  root-canals,  26 
in  preparation  of  roots,  36,  43 
use    of,    for    cementing   crown-    and 
bridge-work,  148,  169 

Heat,  use  of  as  a  disinfectant,  13,  24 

Hollow  wire  for  posts,  86,  127 

How  crowns,  49 

How  screws,  49,  56 

How's  root-trimmers,  34 

Howland  crown,  57 

Hub-mold,  97 

Hygienic    condition   of    the   mouth   as 

affected  by  bridge-work,  206 
Hygienic  consideration  of  collar  crowns, 

124 
Hygienic  preparation  of  the  mouth,  6,  9 


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